Cpanel Linux Server Help

I have a linux server running cpanel and I'm having problems with it sending out emails. I've only had the server for a few weeks and I had a invite script installed on it and invite emails were being sent just fine but then two days ago my server got stuck so I contacted the hosting company and they said my sever had overheated so they moved it to a cooler place (all servers should be in a cool place duh). Anyways every since they moved the server the invite emails don't get sent out. My server has the same ip address I didn't change anything with the invite script, I didn't change anything at all but obviously something got messed up. They looked into it and said it wasn't resolving the hostname or something and that they fixed it but it's still not sending emails out. My server's ip is not blacklisted according to spamhaus and I just want things to work like they were before. If you are experienced in configuring a linux server to send out emails rather it be installing SPF records, domain keys, etc... I just want my server to send out emails like it was before with my script. Please help :-)

Linux Script Install

Project ID: #293839

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