Have you experienced that in Sitecore, the EXM Email Experience Manager window keeps reloading?
In my solution, the problem was that I have a cookie with a “:” (colon) in the cookie name. According to the old RFC 2616 specification, colons are not allowed in cookie names.
Although this is not a problem in the website or in the Sitecore Shell, it causes problems when this particular SPEAK app calls the server API.
The solution is to avoid using colons in cookie names.