Some email addresses can't be used coz they falsely decided my mailserver is a spam source.
Considering how few email messages are sent out, and they are only sent to people for account notifications, it's really just a royal PITA.
So if the web page says you can't use an email address, it will be because the mailserver you want says I'm a spam source.
That's a shame. Have you tried submitting a retraction to all of the regular RBLs?
Anyway, I guess I'll have to look into setting up another email account on a different provider, though I have trust issues with free providers, especially given that its going to be used to set-up a mining account i'd like to make sure its secure.
-Snip-
Just spin up a new address from gmail or other free email provider and use that.
I had bad experiences particularly with gmail in the past with accounts being hacked on a regular basis, so wont even go there.