why am I getting a syncing error?

I get this error code when trying to sync my daughters new iPhone with my iTunes account.

What can I do to be able to sync her phone again which I used to be able to do?

iPhone 6s running 9.3.5

I have tried to authorize this computer but it states that was already authorized, and then tried to de-authorized my computer and then authorized it back again and got same error message.

thanks