I have the galaxy s25 ultra. When I'm on phone or speaker, it will not let me use the keypad to push the selection(like 1,2 0r 3) top make the selection.
I just want to make sure you're not making the same mistake I've done a few times. Let's say I call my bank and I have to type in my account number using the keypad. I don't have it memorized so I open my bank app, while still on the call, to get my account number. When I need to go back to the call to type in the number (here's where I've made the mistake) I hit the phone icon instead of swiping down from the notification panel to get back to the ACTIVE call. Doing that will bring up the number keypad, but any numbers I hit will not register in the call because I'm technically not in the active call....does that make sense?
Try clearing out the phone app cache. Touch and hold the app, the you will get an applet popup. Click on the tiny circle with an "i" in it and the phone app properties will show.
