I found a work around for this issue..
Before explaining it, let me summarize the issue again. I have Navigraph subscription and ANF function is working before take off. There is no issue with it. BUT, after take off and climb, when I switch to PLAN mode and zoom in to set the BTV function, it was giving this error. Again, it is working before take off during taxi from gate to runway.
For the work around, after get in the cockpit in the cold and dark situation, I wake the plane up and directly check the OIS settings. If it shows the current airac version then it is good to go. But sometimes, even though I logged in with Navigraph subscription, it is showing QR code to log in. If I continue like this, I am able to access the charts and ANF before take off but not not BTV or destination airport. Therefore, when I see the QR code there, I am just going back to main menu and start the flight again. With this way, it seems it is logged in again without doing anything and all the systems are working.
Hope I could explain.