Getting Error While Clicking on "Approve Button" in Opportunity Workflow

Need Help…!!!

when i am trying to click on Approve from Action Button, it shows

user does not have access to this document
&
Insufficient Permission For Opportunity

But i have given that specific role to that user, still it showing error.

Can anybody tell the reason why it’s showing like this??

Thank You.

if link other doctype, please add this doctype permission or check config approve permission