Getting too many SMS's error when using SMS MFA

I am using Multi factor auth with the popup signup form. My users keep getting this message “THERE ARE TOO MANY SMSS RIGHT NOW. WAIT SOME MINUTES AND TRY AGAIN.” when trying to add a phone number to their signup. Also it does not send me an sms message, instead it keeps asking for my recovery code every-time I log in.

Does anyone have any suggestion as to what could be the cause? I am on the free plan. Thanks

That may occur if you have enabled multi factor authentication through SMS, did not configure your own credentials for message sending and already used the number of messages available for testing purposes.

As mentioned in the Guardian SMS configuration:

You have up to 100 SMS and up to 10 SMS/Hour per user to test Guardian, these limit will be removed once your own credentials are set up.