People Picker dialogue is blank / Choose folder dialogue under upload documents is blank

People Picker dialogue is blank / Choose folder dialogue under upload documents is blank

Resolution: This is because of the SQL Injection rules in the IIS site.

Follow the below steps to fix the issue:

Go to IIS Manager (inetmgr)

Expand the Sites-> Select the Migration farm URL

In the right side pane-> double click on "Request Filtering"

Under the rules tab -> Remove the  rule for SQL injection

Do the same on the extended site and as well on all the WFE servers in the farm

Hope this helps someone.