Seriously, I’m ready to call this the game that has had the most issues in the history of gaming.
Risky to call it that
Make sure you’re not using a 64 bit browser, battlelog doesn’t work in a 64 bit browser.
Make sure the specific build of your browser contains all the functions needed by the battlelog plugin, lots of functions are being phased out and it wouldn’t surprise me if that broke battlelog on the newest chrome/firefox.
Other than that, make sure it isn’t blocked by your AV, the browser plugin is installed and the PC side of the plugin is installed.
Make sure Tue browser isn’t blocking the plugin. Check the search in the the right if there is a puzzle piece or something.