An agent tries to login into the agent portal and receives the “Your account isn’t registered as an Agent” message.
Check whether the user account already exists or not. It may not be added as an agent in the agent portal, but the account is created automatically and added under the contacts.
You can either use global search, user search, or by using the email ID.
If the user is found, click it to open a profile page. If the agent profile page is opened, the issue is cleared.
If the contact profile page is opened, you can use the Convert to Agent option to convert the contact to the agent.
Note: To convert a contact to an agent, you should have Manage Agent permission.
If the user is not found, go to the Agent module in the Admin center and add a new user as an agent using the Add Agent option.
While adding an agent, you may receive an error message “Email has already been used for another contact account.” This means a user with the same email already exists as a contact. Use the convert to the agent option present on the Contact profile page as explained in this troubleshooting guide.