When i make a bulk action a get Error 504

Hi there,
When I try to make a bulk action for renaming all author slug of my website i get error 504. Then, when I reload the page, no changes has been made.

The server support team told me to ask for the solution to the developer of the plugin.
It seems that the plugin overcome the servers timeout limit.
They tried to edit the folders permissions and moving the dynamic timeout limit but they had no luck.

Could someone help me to solve this problem? Thanks a lot in advance for any help.