e9006^Verification failed during extracting details from signed data - Credentials are invalid

Reason

This error happens if

1. If you haven't completed your dsc registration or dsc renewal

2. If there is a mismatch in the detail you entered in the authorization signatory

3. If you are signing with wrong signature  not the one you have registered in the site

Among these 3 reasons 1 and 2 are most likely cause for this error

Solution 

Signature invalid - Error during signature verification -signature seems to signed in future

Solution

This is a simple fix , all you have to do is change your date to 2 or 3 days backwards from current date

Validity unknown or signature not verified in c form ,delivery note or other pdfs

Reason

The main reason for this error is that digital signature added in the PDF have not  yet been verified by the system