Apple Two-Factor verification code to phone

[Chrisfrom3TFM]

I recently switched network from Three to Sky Mobile and I'm having an issue receiving Apple Two-Factor verification codes to my new number, have contacted Apple who said it sounds like a network issue, wondered if anyone else had a similar issue, I receive a message saying "Too Many Codes Sent" and it won't send via text or phone call?

Thanks.

[caesarome]

@Chrisfrom3TFM 

A few things to try:

Check your phone isn't blocking unknown numbers. Go to Settings > Messages > Unknown & Spam > Filter Unknown Senders > Turn off.

If you use message filters on iPhone, make sure all messages are visible. Go to iMessage > Filters > Change to All Messages.

Turn off any VPNs.

Check the spam folder of your messaging app for these texts.