It's a bit of a nightmare here when some say to clear the cookies and cache to possibly resolve issues like these. Neither will work and it can cause more hassle really.
Clearing cookies - cookies basically just save preferences. They have absolutely no bearing whatsoever on server side issues. Clearing cookies won't do anything at all and will mean that when you next visit any website, you'd have to accept cookies over again via those annoying popups.
Clearing cache - cache is really just a folder that contains downloaded website files such as logos and other imagery. The first time someone visits a website, files will be cached (downloaded) for fast access when visiting the website the next time (as the files will already be there). The only reason to clear the cache at all is to free up space on a hard drive or improve system slowdowns (clearing cache will remove files of things someone may not have visited for quite some time and thus it's taking up unnecessary space).
Using another browser - it really depends. Some browsers may not work as well running different plugins (the late flash, html5, java). A recent platform update may not work well with some browsers so it couldn't help to try it.
Realistically though, if the issue still happens whilst trying to do the same thing in an incognito browser window (incognito is no pre-saved cookies or cache), then actually clearing the cookies and cache is just setting yourself up to have to click "accept cookies" over again when visiting websites.
