[galaxy-dev] login problem (redirection to the login page)

Hi, this is not the first time I encounter this problem : I change the authentication mode (external to internal). And since then I cannot login with any account. Each time I'm redirected to the login page. Yet I haven't any log error. I have the galaxy-master 15.07 version. I cleared the firefox cache and cookies, from the browser and command line. But the problem's still there. The last time I uninstalled my postgresql database. I saw this post : http://dev.list.galaxyproject.org/Login-problem-tt4139426.html Is there a way to find the modifications (without unistall my galaxy instance) ? Thanks ! F.T