Who solved the problem with this disaster?
The trouble is getting letters signed by DKIM in spam. SPF is.
Text letters go to inbox.
Letters that do not contain my new domain also fall into the inbox.
Long struggled with this problem.
Servers are white, i.e. no black list has ever been listed. DKIM / SPF / PTR is OK. From googl'a got something like: "Your server is not listed in any white list."
After filing an application for https://www.dnswl.org/ and adding our servers to the lists, we no longer faced similar problems.
All emails get into the Inbox!