Yep, got the same error this morning, out of the blue it seems.
I did a fresh install of all the Horizon View pieces last month and all were set up with CA signed certs and I used the certificate automation tool to make sure everything was minted and trusted. Everything was green until this morning. It appears I have the exact same symptoms that you do. I verified the Composer and Vcenter server and they went green. Working now to turn the View server green again. Thanks for the post.
