Old MFP that cant speak new SSL/TLS Old java based application that doesnt respect all email flags and will often just close the connection even mid successful

Old MFP that cant speak new SSL/TLS Old java based application that doesnt respect all email flags and will often just close the connection even mid successful auth. New server that lives in the cloud, but doesnt match up with the right protocols to send email out of Azure and into 365, so its punted down to on prem and back up to 365 just so Microsoft can sleep better at night. These are the most common reasons I have seen.