GameSparks Plugin sending this request timeout error

When I send a request with a large input parameter(string or json ~150 kb), I get an timeout error. I satting request:setTimeoutSeconds(30), but its not helps. (When i sending this request via the Test Harness its take less then 1 second and its ok)

I started changing the size of the parameter. 

I reduced the size of the request to 20 kb. Still did not work. When the size of the request became 16 kb, the request was processed successfully. I think there is some kind of restriction on the volume of the query in 16-20 kb. 

Can be api has some kind of limit on the size of the request on the client side in the plugin?

https://support.gamesparks.net/support/tickets/4584 For more information