php can't connect to o365 imap server after application migration

Question

I really tried to fix this by myself in the past 3 days but I run out of ideas.

The thing is that when I was testing the application on azure I didn't have any issues. I already had a windows server VM, where I installed WAMP to test out the PHP app. Everything was fine and working till I migrated the app to another hosting provider where I think they run Red Hat on the VM.

All ports are open for the IMAP and the PHP IMAP extension is enabled.

The thing is that I'm getting an error message when I try to connect to Server

name: outlook.office365.com
Port: 993
Encryption method: TLS/SSL (I tried both, but on the previous server was TLS)

Can't connect to FRA-efz.ms-acdc.office.com,993: Connection refused

Do you have any idea why this is happening?

Thank you in advance!