Have you tried the following by @Hester40MT? From this thread?
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This may be that the “Online” setting in MSFS is turned off. This will happen if your internet was interrupted or when down - either local or your ISP.
There are plenty of topics on this:
Search results for ‘insert disc’ - Microsoft Flight Simulator Forums
You will need to keep trying a few times until it lets you in. Once in, you can change that data setting back to on.
You also can try disabling your internet to see if that lets you in faster.
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You could also refer to this article: https://flightsimulator.zendesk.com/hc/en-us/articles/360015985699-Error-message-Please-insert-disc-