I've found what was the problem: in my SendGrid account there was Link Branding enabled. But that's little bit strange because it was enabled before moving to the new server and it worked fine.
I have NodeBB behind an nginx proxy so requests are forwarded to localhost:4567.
If the user goes through the process of resetting their password, the email they receive contains a link with localhost:4567 and so the link doesn't work.
How can I change this so that the email will reflect the actual domain I am hosting the site on?
@codecowboy set the "URL" property in config.json to your domain
@pichalite thanks that sorted it!
Would you be able to upvote my question so that I can increase my reputation? I have to wait 5 minutes to make a post at the moment.
Same issue I had....
I don't think I did end up solving it as fixing this issue broke emoji.....
I'm small enough to deal with password resets manually for now but can't live without emoji hahahahahaha