I implemented Microsoft Graph authentication and authorization, I used the auth code flow to get a refresh/access token and it works on my localhost and it worked up until yesterday online.
The problem is that now every time a user authenticates he get's redirected to the right redirect_uri, but with a code parameter that seems to be invalid, and I am unable to get an access/refresh token with it.
When I start the flow from my local machine, it still works, I get redirected to my local machine with a valid code and get a valid access/refresh token. It only fails when I start the flow from my online app, even though nothing changed from yesterday when it worked, it always redirects with an invalid code.
The code itself is huge, it is usually was 45 characters and now it is 876... also, previously it started with M.R3_ and now it starts with 0.AQ4AaN-.
Also, the code is always the same no matter who tries to login, tested with multiple accounts and with multiple machines/IP addresses.
Can you help me solve this issue? I will gladly provide more information!
It started working again without any changes on my end, no changes where made in code or azure app.
I still don't know what happened and I would like to know how to prevent this failure in the future.