Question: I tried multiple combinations you have suggested on your Earthlink setting page, but nothing works.
Please Please Please - help with with settings that you can check yourself on your Mac first.
I used your MaxBulk (paid version 8.5.4US) for many years and now my business stopped...
Answer: If you look at your connection log you will see what the error is:
 5/3 13:50:10 > AUTH PLAIN Mipco **********
504 5.3.3 AUTH mechanism PLAIN not available
Just set the login scheme to LOGIN instead of PLAIN. It is a pull-down menu next to the authentication setting. When connecting your server sends some welcome text, in that text you can see what it supports, in this case it supports LOGIN and CRAM-MD5.
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