Delayed Verification Text Messages, or not receiving at all.

When I log into subscribed sites such as T-Mobile, bank websites, etc., I am not receiving the verification codes required to sign in for several hours. The latest attempt was delayed for 12 hours.

I have not installed any new spam or security features. I have tried several reset methods including switching airplane mode, turning phone off/on and checked all settings.. Has anyone experienced this, how can I fix it?