cURL 6: Couldn't resolve host ''

A number of my websites that use the WP-Defender plugin have been giving a 504 Server error. I think I narrowed it down to WP-Defender throwing the error:

cURL 6: Couldn't resolve host ''

Disabling the WP-Defender plugin seems to stop the constant 504 errors. I also can't update the WPMUDev dashboard, I tried on a few sites and it just doesn't update. On one site it put it in permanent Maintenance Mode (I deleted the .maintenance file to resolve that).

I asked my host, SiteGround, about this after doing a search for existing answers on and here is what they said:

"Hello Joshua,

It seems the server it self can not resolve the doman as this is why the connection ends with such timeout. I tried to connect from few different shared and dedicated servers that we use however the connection was not possible.

I think there is a temporary issue with connection to the sub-domain that causes all those issues. Could you please contact the support team of and ask them for more information about the issue.

Best Regards,

Simeon Boev
Senior Technical Support"

So, is there an issue with or other subdomains? Can ya help me out?