You have changed ITMS environment to HTTPs mode only, and communication profiles have HTTP checkboxes removed.
But when you check the ULMagent pull URL and installation XML NS communication protocol you discover that those are still HTTP
The Pull URL on the page is generated based on the SMP Server's ability to find available URL's. The "http" one is taken as a priority if exist. For example if you have a settings when both HTTP and HTTPS binding existed on SMP and had always a HTTP link on the pull page.
Delete port 80 binding from Default Web Site and check "Require SSL"
iisreset & AeXSVC service restart
Now SMP server will be unable to find HTTP URL and start generating the pull URL and NS protocol as HTTPS