The problem is a real one with acymailing. The host is set correctly and has been set the same since we have acymaling (for many, many years ago)
In 5.10.14 20-30% of emails were opened. When they were more important..
In 6.10.3 to 2000 emails were opened 3. We have 6 email accounts and we have opened them and it does not appear in any statistics. 3 gmail accounts in which no message arrived.
In 5.10.14 the score of spam tests is over 7 or 8
In 6.10.3 the same email is under 4 - so it's spam. Moreover, gmail did not even receive emails.
Appears in error test: MIME_HTML_ONLY BODY: Message only has text / html MIME parts - which is rated with 1 point. Error related to html / txt email combination which is probably not provided correctly by acumailing.
And the errors are many and only related to acymailing.
Waiting for someone from acymailing can get involved in the answer.