Phone number authentication problem

Hi friends
I have a problem with firebase authentication not working for me
I have watched all the relevant videos explaining this feature, but I still struggle with this issue.
My problem is only in the phone number. No phone number is added to the data and the verification code is not sent. What is the solution, please?

Add SHA1 key to your firebase project, re-upload the new json file (named google-services.json) in asset and it should be working fine.