An AJAX HTTP error occurred. HTTP Result Code: 504 [#2855181]

Hi,

I am able to connect to the email using the Mailhandler Pop3 Settings. It connects successfully, also displays the number of emails in the mailbox. However, when creating a Mailhandler SOurce, it gives me the below error -

An AJAX HTTP error occurred. HTTP Result Code: 504 Debugging information follows. Path: /Openoffice/batch?render=overlay&id=683&op=do StatusText: Gateway Time-out ResponseText: 504 Gateway Time-out The server didn't respond in time.

I have changed the max_execution_time/ max_input_time/ memory_limit in the Php settings file, but to no avail.

Could someone please guide me to a solution?

I am using the mailhandler to import user's email. The Mailhandler works fine when using the IMAP settings, however, in IMAP it imports only the unread emails which is not a feasible solution as the users tend to check their email on multiple devices & this results in mailhandler not importing all emails.

Kindly guide me.

Thanks