Try to connect to portal.checkmk.com and get a request error. Is the portal currently down?
Same here.
http redirects to https where the tcp connect succeeds but then no further response is being received.
It’s back working as far as i can tell.
They must have some good monitoring system in place that quickly detected the outage and notified the sysadmins 
made my day 
so long
@martin.schwarz You know how they say in German:
“Der Schuster hat immer die schlechtesten Schuhe”
Not true in our case, our admins are top notch