This may happen if:

• You’ve denied permission to fetch documents
  Note: Make sure you tap Allow on the DigiLocker screen
• Your PAN is not linked to the DigiLocker account
• The age in your PAN is less than 18 years
• You’ve not ticked the check boxes for Aadhaar Card and PAN Verification Record before tapping Allow.
• You have not signed up on DigiLocker by giving Aadhaar details and OTP verification

Note: 

• In the DigiLocker screen, make sure you enter your Aadhaar number, OTP, and DigiLocker Security PIN properly
• You can upload the PAN image manually if your PAN is not fetched through DigiLocker