iPhone Mail App not syncing with Gmail web UI.
As per the title, my iPhone Mail App is not syncing with Gmail web UI or MacBook Pro Mail App.
I receive emails on my iPhone Mail App, MacBook Pro Mail and on Gmail web UI. If I delete an email on Gmail web UI, my iPhone Mail App and MacBook Pro Mail App (Gmail account) sync Ok. If I delete an email on my MacBook Pro Mail App (Gmail account), both Gmail web UI and iPhone Mail App sync Ok too. BUT, if I delete an email on iPhone Mail App (Gmail account), neither MacBook Pro Mail App nor Gmail web UI sync.
This started happening after my latest iOS iPhone update to 14.2 on 11 November 2020. I've turned the phone on and off (...), checked IMAP/SMTP settings, security, reset the Captcha - nothing works.
Not sure if this is related - I saw a glimpse of a security certificate issue but didn't pay attention as to what it was in relation to (it later disappeared).
I Googled the issue but there seems to be no answer. PLEASE HELP!
iPhone 8, iOS 14