That runs usually well and the TCP call is finished within 25mS.
Approx 2.3 times in an hour it takes a bit longer, up to 120mS.
But if the ISP service is broken or the server does not respond, the TCP call fails.
That happens IMHO within the ESP8266 internal TCP stack and the control to my program is only returned after precisely 12 seconds. That 12 seconds seem to be a timeout inside the ESP firmware.
Since however the server call should be repeated every second, the whole ESP is permanently busy and I can't OTA it any more.
Do you know a way to parameter the internal TCP timeout?