Hi
I searched and found many results about this issue and had applied the fix but still didn't work.
here my case:
manually created a Site collection site owner group (testowners) and assign it with Full Control.
I am a member of the group.
First, I got a "Sorry this site hasn’t been shared with you"when I tried to open Access Request link
So I found solutions and granted full control to the Access Request List fortestowners group
and with more solution steps, I also have reset the site owner group with (layouts/15/permsetup.aspx )and selected testowners as a site owner group.
I also went and recycled all the application pools in IIS and done IISreset as well.
Still, Now I can open Access Request list and see requests but when I tried to approve I got a "Request Approval Failed" but If I tried to Decline then the decline was succeed.
Anyone have been able to resolve this or any other idea I can try, please share.
Thanks in advance
Swanl
