Hi @Laura527, let me see if I can help out here.
Have you tried rebooting your phone in safe mode to see if the same behaviour persists there? Also, have you tried clearing the data for the phone app? No call logs or contacts will be erased by doing this, but it will reset all settings for the app which might do the trick. Find and tap Settings > Apps & notifications > App-info > Phone > Storage > Clear data > Tap "OK" > Restart the phone.
Please return with this information and I will do my best to assist you!
