@Mike220359
Welcome to the Forum.
Have you tried running the Phone Troubleshooter. It will do a line check. https://www.plus.net/my-account/tools/phone-troubleshooter/ (You will be asked to log in.)
If it does find a fault, there is your solution. Don't worry if it says that it has failed as the test can be a bit iffy and may still raise a fault. Check in your account for tickets; any ticket generated can be found here Tickets
Please let us know how you get on.
