This mobile number shouldn't have been registered before with IRCTC in any personal or agent ID. You have to use a new mobile number that you've never used before in the IRCTC.
When you sign up to be an IRCTC agent, you must provide a unique email ID. This email ID also should not have been used in any other IRCTC agent ID.
You must give a scanned copy of your PAN card number, which has never been used in any other IRCTC personal ID. But you can use the same PAN number to sign up for another agent ID if you have already used it for an agent ID.
The applicant needs a valid Aadhar number. After a successful IRCTC agent login, the agent is required to do the e-KYC. This means that his phone number is properly registered.
If someone wants to become an IRCTC-authorized travel agent, they need to provide proof of both their office and home address. If the agent wants to run the business from home, he only needs home address proof