We could not verify the certificate: reason = oscp_error

Help
1

I had a client come into the town hall and he wanted to connect to the public Internet with his Laptop(Windows 11 kinda old) we provide.
But when the system showed action needed and he clicked on it he got the following error message: "we could not verify the certificate: reason = oscp_error". What could the problem be and how can it be fixed?

2

what kinda program that error prints on?

3

This might be a Firefox specific error? OSCP stapling somewhere maybe? [and double check the laptop has the correct date/time set]

4

Does this question have anything to do, at all, with Let's Encrypt?

5

Haven't all of LE's OCSP servers been turned off some time ago already?

None of LE's unexpired certs include OCSP URLs anymore.