> 1. Attempted to send mail through my SMTP server and received the error message 550 5.7.1 Authentication Required, Where can I configure this authentication?
David Harris has implemented ESMTP AUTH CRAM-MD5 for WinPMail. It does a SMTP authentication in accordance with RFCs 2554 and 2195. It will also do the LOGIN and the strange MS AUTH=LOGIN.
Go to Tools | Internet options | (Sending) SMTP, edit the SMTP configuration, select the "Security" tab and then select the SMTP Authorization option as specified by your ISP. Most require the the second or third SMTP Authorization option
There are some ISPs that advertise CRAM-MD5 but do not support it. In this case you should try using v4.5. It has an option to fall back to the less secure options.
Do not use CRAM-MD5 authentication even if it is advertised
The process of logging into the SMTP server to authenticate your identity can take a variety of forms: the server "advertises" the forms it understands, and Pegasus Mail looks through that list, choosing the most secure form it recognizes. Some forms are very "weak", in that they either transmit your credentials as clear text or in a form that can be easily broken, while other forms are "strong", in the sense that it is very difficult to work out your credentials simply by observing the exchange of data between the two programs. Unfortunately, one of the strongest forms of authentication, called CRAM-MD5, is commonly misconfigured on SMTP servers, even at quite reputable ISPs - the server will advertise that it supports it, but will actually fail any attempt to use it. Getting the ISP to realize that they are at fault is a lost cause in most cases - it's almost always easier simply to check this control, which tells Pegasus Mail never to use CRAM-MD5 for this server. You should be aware that you reduce the security of your connection by checking this control: CRAM-MD5 is the only commonly-used authentication form that offers reasonable security, and by disabling it, you force Pegasus Mail to use less secure methods... But sometimes you may decide that being able to send mail is more important than being able to do it securely. The choice is yours.
> 2. Where can I tell the mail reader to leave the messages on the POP server after reading them?
Go to Tools | Internet options | (Sending) SMTP and edit the POP3 setup. Hit the "Download controls" and select "Download only unread mail".
Download only unread mail The usual practice when retrieving mail from a POP3 host is to delete it from the host when it is successfully downloaded. If you do not delete it, you would normally expect to see it again the next time you download mail from the host. Pegasus Mail incorporates a powerful and complicated facility which allows you to leave mail on the POP3 host without deleting it, but only download mail you haven't already seen. Because the POP3 protocol does not actually provide this facility, there are some limitations on this command, the most specific being that if you run Pegasus Mail on more than one machine, each one willhave a separate list of what you have already seen; so, if you download mail using one machine then access your account later from a different machine, you will probably get the mail you downloaded the first time again, where downloading the mail on the same machine you originally used would only show mail which had arrived since the last time you accessed your account. Check this control to instruct Pegasus Mail to attempt to download only mail you have not read. The effect of this control is probably meaningless if you do not also uncheck the "Delete retrieved mail on host" control. Using this feature can significantly increase the time it takes for Pegasus Mail to retrieve your new mail.
> 1.  Attempted to send mail through my SMTP server and received the error message 550 5.7.1 Authentication Required, Where can I configure this authentication?
David Harris has implemented ESMTP AUTH CRAM-MD5 for WinPMail.  It does a SMTP authentication in accordance with RFCs 2554 and 2195.  It will also do the LOGIN and the strange MS AUTH=LOGIN.
Go to Tools | Internet  options | (Sending) SMTP, edit the SMTP configuration, select the "Security" tab and then select the SMTP Authorization option as specified by your ISP.  Most require the the second or third SMTP Authorization option
There are some ISPs that advertise CRAM-MD5 but do not support it.  In this case you should try using v4.5.  It has an option to fall back to the less secure options.
Do not use CRAM-MD5 authentication even if it is advertised  
The process of logging into the SMTP server to authenticate your identity can take a variety of forms: the server "advertises" the forms it understands, and Pegasus Mail looks through that list, choosing the most secure form it recognizes. Some forms are very "weak", in that they either transmit your credentials as clear text or in a form that can be easily broken, while other forms are "strong", in the sense that it is very difficult to work out your credentials simply by observing the exchange of data between the two programs. Unfortunately, one of the strongest forms of authentication, called CRAM-MD5, is commonly misconfigured on SMTP servers, even at quite reputable ISPs - the server will advertise that it supports it, but will actually fail any attempt to use it. Getting the ISP to realize that they are at fault is a lost cause in most cases - it's almost always easier simply to check this control, which tells Pegasus Mail never to use CRAM-MD5 for this server. You should be aware that you reduce the security of your connection by checking this control: CRAM-MD5 is the only commonly-used authentication form that offers reasonable security, and by disabling it, you force Pegasus Mail to use less secure methods... But sometimes you may decide that being able to send mail is more important than being able to do it securely. The choice is yours.
> 2.  Where can I tell the mail reader to leave the messages on the POP server after reading them?
Go to Tools | Internet options | (Sending) SMTP and edit the POP3 setup.  Hit the "Download controls" and select "Download only unread mail".
Download only unread mail  The usual practice when retrieving mail from a POP3 host is to delete it from the host when it is successfully downloaded. If you do not delete it, you would normally expect to see it again the next time you download mail from the host. Pegasus Mail incorporates a powerful and complicated facility which allows you to leave mail on the POP3 host without deleting it, but only download mail you haven't already seen. Because the POP3 protocol does not actually provide this facility, there are some limitations on this command, the most specific being that if you run Pegasus Mail on more than one machine, each one willhave a separate list of what you have already seen; so, if you download mail using one machine then access your account later from a different machine, you will probably get the mail you downloaded the first time again, where downloading the mail on the same machine you originally used would only show mail which had arrived since the last time you accessed your account. Check this control to instruct Pegasus Mail to attempt to download only mail you have not read. The effect of this control is probably meaningless if you do not also uncheck the "Delete retrieved mail on host" control. Using this feature can significantly increase the time it takes for Pegasus Mail to retrieve your new mail.  
