error to login to the WPMU DEV dashboard

when i try to login to the plugin it gives me this error:

Your server had a problem connecting to WPMU DEV: "cURL error 7: Failed to connect to port 443: Network is unreachable". Please try again.

If this problem continues, please contact your host with this error message and ask:

"Is php on my server properly configured to be able to contact with a POST HTTP request via fsockopen or CURL?"

i asked to check this things and everything seems ok.

What could be the problem?