I have been using AcyMailer a long time, and have been on Version 5 since it was released without any problems. I always keep my version up to date, and am on version 5.10.12. Today I decided to upgrade to version 6 and installed 6.8.1. Immediately I began having HTTP 500 Errors at every step.
I say others who had this problem and your support wanted to go in and take a look. Please contact me so I can get you set up with access.