How to undo a "Do not ask me again" tick box on Samsung note 8

[Android Central Question]

Hi.

So I had a finger error where I prevented my phone from sending sms's to suspicious numbers ie. 5 digit numbers where I could get subscribed and incur costs. Thing is, I now need to undo this, in order for one of my apps to be authenticated. I have looked in blocked no.s in messages and dont see any specific no.s blocked. Also tried deleting and reinstalling the app however still no luck. Any suggestions will be welcome. TIA

 

[B. Diddy]

Welcome to Android Central! Look for an option to turn on Premium SMS, as described here.