Q:

Sharepoint Reports do not work in Firefox

Using SSRS in integrated mode, Reports can be viewed in IE but not in Firefox, Chrome, Safari, etc.  They get "An unexpected error occurred while connecting to the report server. Verify that the report server is available and configured for SharePoint integrated mode." (Oh, and it also happens to one IE user on the domain as well)
It might be a double hop issue, since we do have a dual farm (frontend and report server).  I've been following directions pertaining to double hop authentication, and I'm currently using setspn, all to no avail.  I cannot find anyone else with this problem.  This is really frustrating.

A:

Firefox by default has NTLM and Kerberos authentication disabled. Websites smart enough to detect this give an appropriate error page. SharePoint isn't that smart.
Enable Negotiated authentication by opening "about:config", search for "network.negotiate-auth.trusted-uris" and set it to the domain name your SP server is in (ie if your SP server is sp.example.com, set the value to example.com). You may need to se the "network.negotiate-auth.delegation-uris" too, depending on your configuration.

