Can't login to dashboard from client's website

Hi Guys,

I have just installed the WPMU DEV Dashboard plugin but when I try sign-in with my account in order to get plugins installed, I get the following error:

Your server had a problem connecting to WPMU DEV: "HTTP Error: 500 """. 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?"

See screenshot attached.

Is there any other way to fix this or I can get the plugin installed without doing it directly via the dashboard?

Kind regards,