Version 4.9.0 is more than 6.5 years old
I am afraid that we really can't provide support for such an old version
On top of that, you are using PHP mail functions as a sending method in your AcyMailing Configuration
It is virtually impossible for us to debug this sending method because we don't receive any kind of feedback from it. That function just forwards your email to the underlying email server and that is it. In order to see what is going on and why your emails are not delivered or why spam test is not working, you should do one of the following:
- contact your hosing support and ask them to inspect email server logs. They might tell you why the emails are not delivered
- use an external server as your sending method. Configure SMTP server and use it instead. That will give you possibility to test the whole sending path and see what is going on