[quote user="pol098"][quote user="idw"]You might want to check out DavMail ...[/quote]Thanks. Could you clarify that a bit please[/quote]

It's pretty easy, just works as a gateway which does all necessary communication with the Exchange server and can be accessed via the localhost address for POP, SMTP and IMAP access.

Download the Windows setup from <http://davmail.sourceforge.net/download.html> and run it, then follow the instructions at <http://davmail.sourceforge.net/gettingstarted.html> and take an additional look at <http://davmail.sourceforge.net/advanced.html> for further options. My setup for SMTP looks like shown in the screenshot below:

Problems with SMTP on Office 365

I have just had my email provider changed from Demon Internet (bought out a few times since I started, ultimately owned by Vodafone) to names.co.uk; email is implemented by them via Office365 (Exchange Online). I have been able to get Pegasus 4.72 working (I'm not using Mercury) to receive mail via both POP3 and IMAP, but am unable to get SMTP working for sending. This is not a major issue as I can use another SMTP server, but I'd like to get it working.

There are various Web sites that give the SMTP and security parameters, simple enough:
- Server name: smtp.office365.com
- Port 587 (25 should also work, but is not recommended; it gives me exactly the same authentication error message as 587)
- Login details: same as POP3, email address and password.
- No alternate address or domain name in HELO/EHLO (and using 0.0.0.0 makes no difference)
- Use SSL/TLS Via STARTTLS (neither never nor direct SSL work at all)
- Disable certificate validation ticked (unticking this makes no difference to the SMTP log)
- Don't (untick) use SSLv3 (ticking this does not help)
- SMTP authentication using specified login name and password (same as POP3). Trying prior POP3 login, and login using a POP3 name/password, do not help.
- Untick "do not use CRAM-MD5" (ticking this does not help)

Choosing some options causes an earlier failure, but with everything as above the send fails with the following SMTP log information (modified only to remove possible security risks, n is numeric,  l alphanumeric)
20:11:27.304: << STARTTLS
20:11:27.328: >> 220 2.0.0 SMTP server ready
20:11:28.496: [*] SSL/TLS session established
20:11:28.496: [*] ECDHE-RSA-AES256-SHA384, TLSv1.2, Kx=ECDH, Au=RSA, Enc=AES(256), Mac=SHA384
20:11:28.496: [*] Peer's certificate name is '/C=US/ST=WA/L=Redmond/O=Microsoft Corporation/OU=Microsoft Corporation/CN=outlook.com'.
20:11:28.496: << EHLO [192.168.200.1]
20:11:28.523: >> 250-DB6PRnnnnCAnnnn.outlook.office365.com Hello [nnn.nnn.nnn.nnn]
20:11:28.523: >> 250-SIZE 157286400
20:11:28.523: >> 250-PIPELINING
20:11:28.524: >> 250-DSN
20:11:28.524: >> 250-ENHANCEDSTATUSCODES
20:11:28.524: >> 250-AUTH LOGIN
20:11:28.524: >> 250-8BITMIME
20:11:28.524: >> 250-BINARYMIME
20:11:28.524: >> 250 CHUNKING
20:11:28.524: << AUTH LOGIN
20:11:28.549: >> 334 llllllllllll
20:11:28.550: << lllllllllllllllllllllllllllllllllllllll=
20:11:28.577: >> 334 llllllllllll
20:11:28.578: << lllllllllDBL
20:11:35.114: >> 535 5.7.3 Authentication unsuccessful

If I try to log in with an incorrect password I get the same dialogue (with differences in the last numbers).
I have checked and rechecked name and password, both typed and pasted in.

I have rung names.co support; they confirm that the same name and password are used for POP and SMTP, and find nothing wrong.

 Does anybody have any suggestions, please?

Don't know if it will help but you could try the second option for authentication under the security tab.

[quote user="caisson"]Don't know if it will help but you could try the second option for authentication under the security tab.[/quote]Thanks. I think you mean "Use SSL/TLS Via STARTTLS". Neither never nor direct SSL work at all; that's the only one of the three options that gets anywhere, and the one I've been attempting to use mostly, as I said. Unlike the other options it connects, but then fails authentication. I think I've tried just about everything possible (my original question says briefly for the various conceivable options things like "ticking this does not help"). Best wishes, pol098

No. Under SMTP Security | Authentication  you are using the third option. (Same credentials as POP3)

Try the second option, specifying the Username and Password. 

[quote user="caisson"]

No. Under SMTP Security | Authentication  you are using the third option. (Same credentials as POP3)

Try the second option, specifying the Username and Password. 

[/quote]Thanks. I was probably unclear in posting my original question, in an attempt to keep it brief. In my original post I said "SMTP authentication using specified login name and password (same as

POP3). Trying prior POP3 login, and login using a POP3 name/password, do

not help"; this could be expanded: for most attempts I used "Login to the SMTP server using the following details" (with the same name and password as used successfully for POP3). I have also tried "Login to the SMTP server using a POP3 username/password" with the same failed authentication, using a POP3 profile that works. "Do a prior POP3 login to authenticate before sending mail" didn't even get as far, as was to be expected. In the authentication section ticking "Do not use CRAM-MD5 ..." prevented getting as far the one or two times I tried. I think I have tried all sane combinations of options, and some insane ones. The only thing I didn't bother with is certificate fingerprint tracking, never ticked. For most attempts I ticked to disable certificate validation; I enabled it once or twice, to no avail. Restricting to SSLv3 didn't work at all (Office365 uses TLS, hence no surprise).

I've tried both with the OpenSSL DLLs supplied with Pegasus (not the latest even when 4.72 was released, due to problems with the OpenSSL version then current), and the latest available openssl-1.0.2j-i386-win32.zip (which hopefully would have the earlier problems fixed); they (mis)behaved identically for SMTP, and both work fine for POP3.

If you use it, try disabling any AV scanning of your pmail installation, and turn off email send/receive checking.

[quote user="Greenman"]If you use it, try disabling any AV scanning of your pmail installation, and turn off email send/receive checking.[/quote]The only virus scanning I have is Microsoft Defender, which can't be disabled permanently, and I don't do any send/receive checking (I do a manual selective mail download when I choose to, and send mail immediately). I disabled Windows Defender temporarily, expecting no change, and indeed it was exactly the same: SMTP sending fails authentication. I'd suspect the name and password, except that I've checked them thoroughly, typed in manually, and copy/pasted, confirmed that they work for receiving with POP3. So everything unchanged: POP3 receives from Office365 with a certain login name (email address) and password; SMTP doesn't send with the same credentials. Has anybody used Pegasus to send mail via Office365 recently? I believe there have been significant changes in the way Office365 (as used by my email provider, names.co.uk) works; I had wondered if Pegasus might have stopped working in this context. Can there be an issue with Pegasus Mail/OpenSSL TLS support?

Two thoughts...

1) run the encoded login credentials from a log through an online decoder like base64decode.org to verify what is being transmitted.

2) start from scratch with a new SMTP host configuration file.

Also,  I did a quick web search which brought up the issue of Office365 (Exchange online) requiring a license be assigned to each user.  I don't know whether that is a consideration in your scenario but here's the URL to that site.

http://answers.microsoft.com/en-us/msoffice/forum/msoffice_o365admin-mso_dep365/office-365-smtp-settings/0ca61631-10fe-42e8-a8c6-d2e3441d2a0c

[quote user="Brian Fluet"]1) run the encoded login credentials from a log through an online decoder like base64decode.org to verify what is being transmitted.[/quote]Thanks again. I wasn't aware that this dialogue was just base64-encoded. Did that, got "Login:" and "Password:" prompts, and my user name and password (confirming they had been entered correctly). Amusing to think of the people who've posted these gobbledegook strings, thus revealing their passwords to all and sundry ...

[quote user="Brian Fluet"]2) start from scratch with a new SMTP host configuration file. Also ... the issue of Office365 (Exchange online) requiring a license be assigned to each user.  I don't know whether that is a consideration in your scenario but here's the URL ...[/quote]Been there, got the tee-shirt ... A new SMTP profile worked exactly the same. I'm using a commercial Office365 Exchange online service: I had an account with Demon Internet, which has just stopped supporting email and allowed names.co.uk (only) to takeover the domain, so I have bought an Office365 service from them. Their technical support can find nothing wrong in my configuration and say I should be able to receive mail via POP or IMAP through this account (I can) and send via SMTP with the same login. I have the necessary licence, which I've checked in Administrator mode - if I didn't have a licence I wouldn't have a mailbox at all.

 So at the moment the problem doesn't appear to be any local or administrative (mis)configuration I can deal with, but either an incompatibility between Pegasus and current Office365 (which might have changed since people reported success with Pegasus), or a problem with the setup by Office 365 service provider names.co.uk.

 Unless something promising comes up, my next step should be setting up a different email system and seeing if SMTP works.

Best wishes

Re this question which I originally posted: I've now been trying with SendSMTP, a standalone SMTP sender supporting TLS1.2, SSL3, etc. with the same result, unable to send via Office365 Online. This program's logging says explicitly that SSL negotiation is successful, but authentication then fails. Also people have reported connecting to Office365 with Pegasus, so this doesn't seem to be a Pegasus issue. Rather than try to resolve this, I'm tempted to use another SMTP server, e.g., my ISP's from a fixed location, a Gmail account when travelling. Thanks again for the suggestions.

(Original poster here.) News update, a little information but no progress. I've spoken to NamesCo, who are providing me with an Exchange365-based service to the same address  I used on the now discontinued Demon Internet mail service (hence I can't change ISP or mode of service). They simply say that Pegasus is not compatible with Office365 mail, without any detailed reason. From my experience I know that Pegasus works with POP3 and IMAP; I can of course use Pegasus with the Office365 POP3 and IMAP servers, and another SMTP server for outgoing mail. No detailed reason is given; I'm simply told that applications known to work are Outlook Web Application  at http://portal.office.com,  Outlook 2007 or later, Windows Mail for Windows 10, Outlook for Mac 2011 or later , Windows Live Mail (POP & IMAP only), Thunderbird (POP & IMAP only)  (i.e., they say only Microsoft Outlook supports SMTP this way). So, unless somebody somewhere comes up with a solution, using Office365 from a non-local IP address not known to Office365 does not support sending via SMTP. Office365 mail can be used, I should think, with any email client that supports SSL to receive by POP3 and IMAP, and most clients can be configured to use a non-Office365 SMTP server for sending mail. So for practical purposes Pegasus works fine so long as another SMTP server is found. Google Gmail accounts provide a relaying SMTP server usable from any address with account credentials, although I've heard that some people have problems.

I'd be interested to hear why Outlook365 won't supply SMTP service to non-Microsoft applications, but the availability of other SMTP servers out there makes it a fairly unimportant issue.

You might want to check out DavMail ... I was forced to use it with an Exchange server which I wasn't provided any other remote access for than the Outlook web interface.

[quote user="idw"]You might want to check out DavMail ...[/quote]Thanks. Could you clarify that a bit please, I had previously looked at the Web site but it didn't seem relevant? I don't want step-by-step, just an indication of what to install (on the device I want to be able to send mail from via any Internet connection) and configure (on the Exchange 365 account provided by my ISP). Let's say I am travelling with a phone with an email client supporting SSL, and with Java support (though of course only for applications suitable for the screen size and so on). I have Internet connectivity either via my mobile telephone service or WiFi AP. I have an administrator account with my ISP's Exchange 365 Online, and a mailbox account; I wouldn't expect to log in to them on the road, but can set them up beforehand, with the intention of having POP3, IMAP, and SMTP server support. In practice I can easily set up POP3 and IMAP, but cannot authenticate to the SMTP server (I haven't tried using DavMail in any way).