Default SMS app issues

[Android Central Question]

Would some kind soul be able to help me get my default sms app changed?
I click on it and nothing happens.. its like i'm locked out of being able to change it.

I can make and receive calls.. and can receive sms but cant send,

Any help very very appreciated.

I'm running android 6 on a galaxy s3... I have got everything else working except this one thing.

Cheers

 

[B. Diddy]

Welcome to Android Central! Which texting app are you using right now? Which carrier are you on?