When I try to send e-mails PM's window becomes "milky" and I have to close the program - the program became unresponsible and it has to be closed forcefully (I am asked by windows ...) .

Those "not sent" e-mails now line up (14 already) in some "!to-be-sent" queue and pegasus asks me each time at startup if I now want to send them.

But this does never work.

If I deny to send this e-mails (at the start of PM) I can get into PM and can retrieve and read e-mails as if nothing is wrong.

But "sending" just does not work anymore.

I remember I had this problem about 15+ years ago but I don't remember how I fixed it.

Can someone help?

Would suggest having it create internet log files and look at what is happening in the smtp log.
Must be some kind of error that the log file would show.

Perhaps Provider has changed a setting in the authentication process.

Which smtp server are you using and what port and ssl option if any?

@DonPedro , don't post the entire contents of an internet session log. It will contain the authentication credentials being used, possibly encrypted so not recognizable, but the encryption can be easily decrypted. Instead just post entries that appear to indicate a problem. Normally, whatever is causing the failure is in the final entries in the log.

To enable internet session logging, tick its checkbox located at the bottom of the General tab in Tools > Internet options. Once enable, do a test send of a single message then turn it off.

Log files are in a \TCPLogs subdirectory of your mailbox directory. Their extension identifies the protocol that created the log. They are plain text files viewable with Notepad or similar.

I tried to activate the TCPLog but strangely PM does not "save" the setting.

When I quit the program and re-start the just before activated "create internet session log" is again un-set.
The TCPLog directory stays empty, no file there.

What is now the problem?

I solved the first problem by deleting the mails in the "to-be-sent" queue and found an e-mail which I wanted to be forwarded to be the culprit. for some reason PM was not capable to "handle" this e-mail correcty and froze. From there on the problem started. But I regard this problem as "fixed" now.

But what is the problem with PM not "setting"/accepting the "create internet session log" - box?

It certainly does, but it's always reset when closing Pegasus Mail so people don't pile up large amounts of log-files inadvertently. If wanting to keep it enabled you may use the respective commandline option when launching Pegasus Mail - but then don't forget to disable it later on: There's an item for looking up which one in Pegasus Mail's Help menu.

To log a sending failure, the steps should be to check the "Create Internet sessions logs..." box, click OK to close that window, do a message send, uncheck the logging option to turn it off, then analyze the resulting log file.

When you said that you regard the problem as "fixed" did you mean that you can now send?

@Brian Fluet
Yes, the problem with not sending I now regard as gone. Not really solved because I do not know what the real cause was that made PM freeze, but by deleting the one email that made PM freezing now lets me send emails again.

@Michael
Thank you for remark. That is it! (Should be mentionned in PM's help file ... I read it to learn how to activate logging but I erroneously thought that I have to restart PM to make it logging. My fault).

Question? Was it a forward without editting?? Have sometimes seen if you try to forward without editting just to send the message to someone else. Seems that would work fine, but it often doesn't work, since it retains the original senders info, and it the appears that the sender is that person, and not you, and your are not using your info. So either your server or a server handles it thinks it is some kind of invalid sending.

Could be a lot of things, and without seeing details from log would be hard to say.

Glad it seems to be worked out.

Would have been nice to see log. Click on make log, and then attempt upload.
Again. Make sure to remove any lines with password and your email since log files have info.

@msetzerii
the problem is/was solved by deleting the email in question from the queue. since it was not my personal problem but a problem of a friend I can not go back to investigate what really was the problem. thank you for your engagement!