I have code which validates a login form (with an option to "remember me") and, if valid, authenticate the user. I then set the forms auth cookie and redirect.
The auth cookie is set as follows, with the persistent argument being true if the user has selected "remember me".
FormsAuthentication.SetAuthCookie(response.UserObject.UserName, persistent);
Response.Redirect(url);
We've tested this in various browsers and generally all is well. However, in Firefox the .ASPXFORMSAUTH cookie is always a session cookie which expires when the browser is closed, even when the persistent argument above is true.
The version of Firefox I'm testing with is 55.0.3 (32 bit). Is this a known bug? Or is there some other reason Firefox might not be letting me set a persistent cookie? Could it be that it no longer accepts persistent cookies as part of a 302 redirect response?