Sorry to all of you. It's an antispam and anti duplicate prevention measure. When signing up from a free email provider (gmail/outlook/etc) the antispam system rates an account a higher risk of being a spammer. Hence it gets flagged for manual approval. We used to have a member of our moderation team that was also able to approve accounts (and used to do so daily), but due to internal changes all moderators were set back to the same level of permissions, meaning only administrators can approve accounts. Currently we have 3 site administrators, however one has not been online since 2018, and the other since August this year as he is very busy with work. The only active administrator comes on every now and then, and I've raised the issue asking if he can approve the accounts the other day.