Confused of link the external links in a webapplication

Hello, im at a client that has published a webapplication. This webapplication has three links (that goes to different webshop with logins Im a bit confused about the behavior. First none of the links worked, the customer had this error.

"Your browser sent a request that this server could not understand. Reason: You're speaking plain HTTP to an SSL-enabled server port. Instead use the HTTPS scheme to access this URL, please."

Then they links to a bypass list, but still got errors. Before we did not have a serverssl profle on the virtualprofile for the protal, but we when they added the serverssl profile Serverssl-insucure-compatible. It worked better. There is one link that does the authentication in the link (like this), i know its no good.

https://www.webshop.com/cgi-bin/sfti/webshop_login.cgi?USERNAME=orange&PASSWORD=apple&HOOK_URL=[er

The apm dont seem to send the link. But still. I cant really understand why it did not work when i had no serverssl profle? And it started to work when i added it? If i have the links in bypass they should just open as normal in the webrowser.