If you receive another error stating that your Aadhar number does not exist or has not been activated, you must visit an Aadhar enrollment centre and present them your correct ID, and proof of address.
If you want to register your mobile number as well then provide them with a valid mobile number and pay for their service. Soon, when the Aadhar number is activated, you can try again to link your Aadhar with your Udyam Registration Portal.