"can't enable starttls" Snappymail issue

Hey there, When I try to login to Snappymail with my mail domain, I get the error “Can’t Enable Starttls”
I can login, if I disable Starttls for the particular domain from snappymail admin. But looking for a proper solution here.

I also tried updating the Cyberpanel meanwhile experiencing the issue, as that has been said to be a common troubleshooting method for this issue. It’s still persistent and I don’t know what to do. Any help will be appreciated.