domain.tld stops processing index.php

[ShinZan]

So today for no reason that i can find, one of my domains quit working.

so if i type in domain.tld (which is a joomla site btw) it prompts me to download the file instead of serving it

if i type in domain.tld/administrator/ the index.php file runs and processes as expected.

If i type in domain.tld/index.php it works no problem. In the interim to bandaid the problem i created index.html in the root that simply javascript redirects to domain.tld/index.php

I had this problem with another account once and i deleted that account on ISCP and recreated it to fix the problem. I don't have that luxury on this account it is a more high profile website that just needs to work.

Any thoughts?

David