Here is an example of the default 120 timeout fail (even though the agent logs log it as a timeout of 300 seconds, not sure what is up with that)

[2018-01-30 16:46:09.331 UTC] [svservice:P880:T976] WinHttpSendRequestWithSSLCertValidation: WinHttpSendRequest succeeded.

[2018-01-30 16:46:09.331 UTC] [svservice:P880:T976] WinHttpReceiveResponse timed out waiting for response

[2018-01-30 16:46:09.331 UTC] [svservice:P880:T976] Retrying in 5 seconds (waited 300 seconds out of 120 max)

[2018-01-30 16:46:14.331 UTC] [svservice:P880:T976] Aborting HTTP request after exceeding time limit (120 seconds)

[2018-01-30 16:46:14.331 UTC] [svservice:P880:T976] HttpComputerStartupThread Pre-startup over HTTP failed: error 0

[2018-01-30 16:46:14.331 UTC] [svservice:P880:T976] HttpComputerStartupThread: failed (computer startup)

As you can see it says it is retrying every 5 seconds for 300 seconds, but it doesn't.  It doesn't try again at all unless you set the timeout to above 305 like I said at which point it does try again at 300 seconds.