M code: security code comes through via email
T Code: security code comes through as text on your mobile device
If an OTP (One Time Passcode) whether email or sms is not being accepted as you get the error below:
The M code or T code is a unique security code that can only be used once within a very limited time frame.
As you enter the code, a drop down menu appears, and occasionally you will select in error one of the drop down number shown. also a typo error occurs that can cause this.
Please check again and ensure you enter the security code within the time frame allocated.