LDAP Auth0 can't connect while other programms do

Hi Guys,

I installed the LDAP Connector from Auth0 on a server inside our private network. But I failed every time to set the settings write. I always get the error message “Testing LDAP bind to LDAP server: Not OK”

I thought it was a problem with LDAP itself, so I tried to use another program that actually worked. The only difference is using the TLS option. So what am I exactly missing here?