cannot connect to W3C Jigsaw validator

Dear,

I have been working on some software that uses the W3C CSS validator.

It has been working fine for a couple of hours but suddenly I can't seem to
connect with this service anymore through my software (I am using a Java
web service implementation).

Also I can not reach the https://jigsaw.w3.org/css-validator website via my
web browser. My internet connection is working fine however, I can access
any other website.

I'm thinking I my IP-address has been blocked or something, because I AM
able to use the validator via my phone's mobile internet (mobile provider).

Also, Windows Connection Troubleshooter reports:

'The remote computer isn’t responding to connections on port 443, possibly
due to firewall or security policy settings, or because it might be
temporarily unavailable. Windows couldn’t find any problems with the
firewall on your computer.'

My 'blocked' external IP is 94.210.181.183.

Can you help me please?

Thank you in advance.

Cheers,
Axel Polet