This is not really a topic for _in_ the forum, it's about the forum site/software itself. I created a temporary email address to register, because the site wouldn't accept my email address as valid.
I do not see any way to contact site admins on this site. Can someone contact me? I should be able to see messages in the next day or so at least, and will return here to look for contact info about logins on forum.smarthome.com.
There are a couple of small free email services that were blocked because so much spam was associated with accounts there. It looks like your alternative provider works fine, you might check to see if you can set up a forwarding rule from the new account to the other one you’ve been using.
The problem isn't my provider, the problem is the forum software not accepting '+' as a valid username character in an email address. My real email I want to register is such. The temporary email address I created only to make an account to post this. I think that email address is already gone. :-)
Who can I talk to about the forum software being able to register me with my intended email address?