I have recently moved all my wordpress-websites from a shared host to a dedicated server. Following the migration, we have experienced trouble accessing the wp-admin on a few of them. The front-end of every site is working just fine, and for the majority of them the wp-admin is working as well. However, on 4 websites i get an infinite redirect loop when I'm trying to access /wp-admin.
We won't get any help whatsoever from our host it seems, so I'm turning to you as I have run out of possible sollutions.
So let's start with what all these problem-sites have in common. They all have the same parent theme for starters. However, a lot of the sites that do work have the same parent theme as the ones that don't, so i'm not sure if the problem lies there. All the sites I use have been installed using the same method, same wordpress-version (3.5.1) and the same version of the themes, and they all look very similar to eachother, and from what I know, there shouldn't really be anything special with the sites that are not working.
What I have tried so far:
Switching of all plugins
Made sure .htaccess doesn't have any redirects in it (also tried deleting the .htaccess)
Changed to standard TwentyEleven theme in the database
I have tried a number of other things as well, that I have found in similar threads, but none of them have worked. I'm not really that familiar with coding and such.
I can't find anything obvious that stands out when comparing the working sites to the non-working sites, but it's hard when you're not sure what to look for. Thus I have no idea of what the root of the problem might be.
Any help would be greatly appreciated, and if you require any more information just let me know and I'll provide it. Have been unable to access this for a couple of days now and I'm starting to get worried!