Refresh token expiry and the corresponding error message

Do they get expired after a period of 90 days inactivity ?

The refresh token is valid for 90 days, according to the documentation.
https://learn.microsoft.com/en-us/azure/active-directory/develop/active-directory-configurable-token-lifetimes#refresh-and-session-token-lifetime-policy-properties

If yes then what is the Error Response returned by the Graph api ?

Here is an example of the error message:
AADSTS700082: The refresh token has expired due to inactivity. The token was issued on 2018-10-19T17:26:59.8511467Z and was inactive for 90.00:00:00.

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