I've seen similar behavior with email from email providers. Has your provider disabled basic authentication?
Based on your comment on using port 25 and 26, my best guess would be your email service is now blocking these ports. Most I work with have forced move to TLS 1.2 at a minimum.
Try using ports 587 (which is default TLS) or 465 - but your connection will need to use TLS - and I don't think UP1.9 supports TLS 1.2 best I can recall.
Another thing you can try is a command line utility called SWithMail (tbare.com - free). I've used it to sort out these kind of issues outside of magic to figure out what was wrong.
Charles Coe, CPA, MCSE
New Orleans, Louisiana