The assistant is confusing you. It is attempting to register you with a SIP provider and create a new account at the provider. Does it not tell you which provider it is suggesting you use? You already have an account with that provider. Deleting the local config does not delete your account at the provider. You do not need to create a new account at the provider. Just tell the assistant that you already have an account, and tell the assistant your id and password. If you lost the password, go to the website of the provider, and they will likely offer to email a reset to you.
For more specific help, you need to mention:
a) what provider you are trying to use
b) what version of linphone (esp mobile vs desktop)
On Wed, Oct 24, 2018 at 9:17 AM, Andrey Novikov <address@hidden> w!
In the linphone program, I launch the assistant and click create user. After attempting to register a phone number, a message appears that the phone number is being used, although the account has previously been deleted. When you try to enter this entry using the same number, a message appears that the entry does not exist.