Try to remove that forward by port 91, let OG connect freely through the router!
Whenever the blynk server does not find the blynk hardware, the blynk app say “Your generic board is not in network.”
Maybe one of these cases: I have one mobile network router Huawei B310 from Vodafone that does not allow OG pass in any way,
the solution was to connect a wifi extender in AP mode and connect the OG to this and its working fine.
Hope this helps.