Note, in case you cannot find the reply, it's above, green area to be unfolded 😉
I will take your word for the fact that it works on the site you set up. I think it is time for me to move on to figuring out how to reconstruct the site. I am doing this as a volunteer, so it may be that we are going to have to reduce the complexity to make it easier to maintain going forward. But that is not your problem!
Thanks so much for all of your help on this. You have really gone above and beyond normal support!
Well, since I already set up the testing site, you are free to test it - do not take my word for it, if I can suggest 😀
4 eyes see more than 2.
However, if you consider rebuilding the site I would lay out a plan along the ideas I communicated here:
https://toolset.com/forums/topic/form-notifications-not-sent-when-using-wp-mail-smtp-2/page/4/#post-1293455
I personally would probably also "bug" the host repeatedly about this issue, because it is simply strange that the same (very same) install works on Server A but not Server B.
We are open to sharing access to the site to your host as well, this is not an issue, hence you can if required share the access with the host company in case they want to see this working and compare to their install/server, because the issue is meanwhile very clearly narrowed to the server, neither the site or database is culprit IMO.
Please let me know if I can help with this elsehow.
Thanks for all of your help. I am going with the "re-build and simplify" approach.