Tell them you have this error: https://www.google.com/search?q=client+denied+by+server+configuration&oq=client+denied&aqs=chrome.0.0i512j69i57j0i512l8.6372j0j7&sourceid=chrome&ie=UTF-8
and that some parts of your admin sectiond don't load.
In those results there are few fix proposals but I'm not sure if they are not security issues if applied. May be somebody may advice. The commands are different for apache 2.2 and 2.4, that's why I asked. Contact your host and they will know what to do for sure.
Also there are results for page_speed conflicts, mod_security conflicts, etc. Might be this also.