can't install ANY packages i keep getting logged out

[Pollyfun]

I use citynetwork and I got exactly the same problem (coming to the login-screen when clicking install mod).
I spent some time testing different solutions, including these:

*In Configuration/Cookies enable/disable Local storage of cookies and Use database driven sessions
*Turning off mod_security with an .htaccess file http://wiki.simplemachines.org/smf/Mod_security_-_Having_problems_with_mod_security
*changing where sessions are saved
  hxxp:support.citynetwork.se/index.php?/Knowledgebase/Article/View/135/0/problem-att-logga-in-i-applikationsverktygets-admingranssnitt [nonactive]

None worked. After more research I found out that the root of the problem is that citynetwork
use the Varnish caching system. Which in turn breaks some of the SMF functionality.
Some info is found here (in Swedish) hxxp:citynetwork.se/webbhotell/varnish-cachning/ [nonactive]

So to fix it the dns-pointers has to be redirected from the standard ip to a special ip
where no caching is used (see above link for ips). Instructions can be found here:
support.citynetwork.se/index.php?/Knowledgebase/Article/View/212/2/editera-dns

In the citynetwork admin panel, select "Domännamn och webbplatser"/"Domänhanteraren".
On the row with the domain (example.com) click on the DNS button.
Find the row that has Subdomän=@ and Typ=A. Edit it and change IP from
188.95.227.20 -> 188.95.227.21.
Find the row that has Subdomän=www and Typ=A. Apply same change.

It might take a couple of hours before the change is active.

[Solid Orphan]

I had the same problem. It made me crazy then I tried to desactivate the varnish cache and it works now. Thanks to you Pollyfun !