Error 503: Unknown domain

Hello,
I moved to OVH yesterday, but my site(studyrr.com) is down due to the following error:

Error 503: Unknown domain - This type of error results generally from a domain ssl certificate not totally installed. If you are a visitor of the website, please try to refresh it or come back in a few minutes.
If you are the administrator of the website, please check the configuration of your server and/or SSL Gateway configuration.

I tried removing and re-installing the certificate but no luck. Can anyone help kindly?