Port Number closed in ESXi 6.7

I have an application accessible with https: // IP-Address:Port-Number.

Installed as a VM in Workstation Pro it is still perfectly accessible.

On the other hand, if installed as a VM in ESXi 6.7 it is not accessible.

If I try to login without the Port-Number, I get a denied access, so in my opinion the port is closed. How do I open it?

Thanks in advance.