At first, my permalinks and all worked.
My permalinks were in `/year/month/post/` format.
Today I found out when I try to open an *Anspress* question, I get a 404. (that worked too, last time I checked) 
Then I read somewhere I need permalink format of `/postname/` to display Anspress questions.

So I changed it to `/postname/`. Now nothing except `index.php?p=xyz` is working. All links to pages throw a 404. I tried changing back to `/year/month/post/` , but that did not help. Tried going to *Permalinks* and clicking *"Save settings"*, but that did not help either. Tried `a2enmod rewrite` (although it has worked before), no help.

I have no idea. It worked 30 minutes ago.