500 Internal Server Error

Hi
I am using a client tool to call the Rest API, this is the URL:
"https://api.lithium.com/community/2.0/yutwg2235/search?q=SELECT+*+FROM+messages+WHERE+conversation.style+%3D+'forum'+AND+depth%3D0+order+by+post_time+ASC+limit+2000"

I am getting the timeout error if i query more records, I don't get the error if I select a small number of records.

500 Internal Server Error
{"status":"Gateway timeout","message":"","statusCode":504}
Error on line 1 of document : Premature end of file. Nested exception: Premature end of file.

How to fix this error?

Regards

Shong