Seems like loops.video has no DKIM or SPF configured (if that's the domain being used to sent activation links/codes), so the tendency is for most email providers to block the mail or move it straight to Spam folder. The situation worsens when many users try to sign-up for an account, so loops.video sends a lot of sequential emails (which is something that could be seen as "spam behavior" by email providers). The developer should ensure that mail delivery is properly configured, particularly the trust headers (DKIM and SPF, as mentioned before) needed for sending emails.