We need to find out the cause to go in the right direction to fix the problem. Because not all causes have the same handling direction.
The first and simplest thing is to try logging in to BM again. Because sometimes it is just a temporary login error, no problem at all.
If it still doesn't work, you can try logging in with another browser. Because when working, we find that browser errors are sometimes easy to encounter.
Next, try checking the wifi network, IP address to see if there have been any recent changes? Because the meta system is very sensitive and easily suspects accounts that frequently change IP addresses.
And finally, if it still doesn't work, you need to check your BM status to see if there are any restrictions by going to Business Manager to see the notification. From there, you can take measures to fix it or appeal if the system's suspicion is incorrect.