Login fails with Firefox 55 64bit

When trying to log in with a 64bit firefox I get this error box. 32bit Firefox 55.0.3 works fine. Is this a tt-rss or a firefox issue? If tt-rss, any idea how to resolve?

tt-rss error 2

Server log:

 - - [13/Sep/2017:18:07:56 +0200] "GET /tt-rss/ HTTP/1.1" 200 29631 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:56 +0200] "GET /tt-rss/themes/default.php?1505242516 HTTP/1.1" 200 416 "https://example.com/tt-rss/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:56 +0200] "GET /tt-rss/errors.php?1505242516&mode=js HTTP/1.1" 200 1238 "https://example.com/tt-rss/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/lib/dojo/nls/tt-rss-layer_ROOT.js?1505318875224 HTTP/1.1" 200 2432 "https://example.com/tt-rss/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/lib/dojo/cldr/nls/en/number.js?1505318875224 HTTP/1.1" 200 846 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/lib/dijit/form/MultiSelect.js?1505318875224 HTTP/1.1" 200 1376 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/lib/dijit/form/ComboBox.js?1505318875224 HTTP/1.1" 200 588 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/lib/dojo/selector/lite.js?1505318875224 HTTP/1.1" 200 2459 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/js/FeedTree.js?1505318875224 HTTP/1.1" 200 4301 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"
 - - [13/Sep/2017:18:07:57 +0200] "GET /tt-rss/lib/dojo/resources/blank.gif?1505318875224 HTTP/1.1" 200 536 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"

All signs point to this being your browser. You probably have cookies disabled… You can try a new profile, turning off extensions, or just re-enabling cookies.

Good luck.

Works fine in 64bit FF for me.

Refreshing Firefox helped (Burger menu | Help | Troubleshooting Information | Refresh).