_Cole_ Hmm, everything looks okay there. PHP and Apache versions are all good, and all extensions are happy. One way to help narrow things down is from the server where osTicket is running, try typing telnet outlook.office365.com 993. You should see output similar to below:
# telnet outlook.office365.com 993
Trying 52.97.133.146...
Connected to outlook.office365.com.
Escape character is ']'.
Note that the resolved IP may well be different for you. If it stops at Trying {IP Address}... then it's failing to connect on that port and you can check any firewall or SELinux logs. Note that even if it does work it doesn't rule anything out completely, as it's possible that something like SELinux would stop PHP from opening the connection via the osTicket files.
You can also try typing getenforce which will tell you what status SELinux is in. If it's enforced, try typing setenforce Permissive which will not disable SELinux, but will allow things it was blocking previously to go through. To revert back, just type setenforce Enforcing or reboot the server (setenforce does not persist across reboots). Also note setenforce needs either root or sudo access!