FWIW I just searched on "nam03.safelinks.protection.outlook.com" that appears in all the gobbledegook and got a lot of hits in the Microsoft forums citing a variety of problems. It is part of an enhanced protection system. Social network links appear to be a common issue in one way or another. I didn't look at all the hits but Microsoft's answer was often ask your server administrator to turn the system off. Perhaps had I dug deeper I might have found another solution.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein