TOO_MANY_REDIRECTS error when iFraming Kibana dashboard using cookies
At first, I thought this all turned out to be a mismatch in the Cookie attributes, alas, it wasn't!
Received some info from the Elastic team...
The cookie which Kibana replies with generally sets the httpOnly flag, and the secure flag (when hosted over https), in addition to the domain. If any of the settings differ for the cookie which you're trying to force Kibana to use, you'll see 2 cookies being submitted and behaviour similar to what you're seeing.
Thought I was setting the cookie with different attributes, but wasn't... ended up using a plugin to get this off the ground: https://readonlyrest.com/