The Internet consists of a set of protocols that are created so that applications like Firefox can talk to each other without any problem or embarrassment. These are the ground rules and what makes it all work.

There now appears to be a breakdown in this connection between Firefox and Microsoft sites. Anyone who uses the Mozilla browser to access these sites encounters an error and is blocked from being able to visit these sites.

If using Firefox outside of Microsoft
This is a problem that seems to have persisted for a few days and has a known cause.  When accessing microsoft.com or other websites of the software giant, users receive a message that they cannot get around.
This is not one of several messages known to users, but the reason seems to be well defined.  Everything happens because Microsoft does not have an active security feature for websites.  We are talking about OCSP.
The problem lies in the OCSP of the visited sites
User complaints already exists They all reveal the same thing.  When accessing microsoft.com or other websites, Firefox detects an error and blocks the user from accessing.  It is also known that this is not a new situation, but everything indicates that it is a problem caused by Firefox.
OCSP is a method that browsers use to verify that certificates in use have not been revoked.  Upon receipt of one of these certificates in contact, he consults the issuer and ensures that it is still valid and usable.  This is where Firefox fails, with stuff uploaded by Microsoft.

Mozilla has already released the fix for this issue.
Several solutions were offered, but Mozilla permanently fixed the problem.  Users will only need to update Firefox to 95.0.1 and everything should be resolved immediately and light up again.
This is not a new situation in Firefox, it has happened many times in the past.  This time it looks like the issue will be resolved permanently and shouldn't happen.  If you are facing this problem, just update Firefox and everything will be back to normal.