There’s an ongoing discussion of similar issues here: Mail and text messages not being sent by Scoutbook? - #9 by BrianDaugherty
It looks like there may be some domain-level issues. If you post there with information about the email domain (gmail.com, hotmail.com, etc) you’re having trouble with, the SUAC folks are trying to collect enough information to see if it’s a system issue or if it’s a domain or cross-domain issue.
