Can I send a link to all users who have not confirmed their registration?
Maybe not all registrations are with bad/fake mail so it is worth sending them the link with activation again? It is worth doing it ?
I have a question what if we confirm all registrations that are not known. Does it increase then the risk of bounce rate and hitting the spam filters ?
Don’t validate email addresses which haven’t been confirmed by the owner. In the event that someone gave an address which belongs to another user it’s a sure fire way to get flagged as spam. That could have long-term implications for your communities ability to send any emails.
It’s crucial you respect email validation and the wishes of users you have invited on to your community.
You could always export the email addresses of accounts which have yet to activate and send a one time email to them outside of Discourse to make them aware of the opportunity.
That exactly what I did after the invitations had expired. Used a separate account that I had them contact me with to make sure they wanted to join, then sent the invites. Those that never accepted were sent private emails as explained above. We did get a few more join.