Load Balancer with certificate in Forwarding rules return 504 gateway timeout at minute

Hi.

I have a legacy application in php 5.6, with the runtime at 3,600.

To give it greater availability, a new server was configured and a DO load balancer was used, this generated the problem that when changing the server, the user’s session is closed, to fix it, Sticky sessions were activated, but this forced me to add the SSL certificate. in Forwarding rules.

However, this started generating timeout with processes of more than 1 minute, I have done several tests and when I use Passthrought in Forwarding rules it allows processes of up to 5 minutes without generating timeout.

At this time I must choose between the user logout every time the server changes or processes fall for more than a minute. Is there a way to modify the timeout of the balancer when using SSL certificate?