is very slow the first time

Hi Guys,

I have a funny situation here - in our production environment the calls to are intermittently but prevalently very slow the very first time. We are talking like 1 minute to 10 minutes delay.
After this is fast as usual.

The funny part is that I see the server side method is executed right away and takes zero time but the callback to notify the client is taking forever.

I cannot reproduce the issue in our DEV environment.

What would you recommend me to do to tackle this?