SSL cert changing with crt - error

Hi all,

we have following certs:
- Root CA Certificate - AddTrustExternalCARoot.crt
- Intermediate CA Certificate - PositiveSSLCA2.crt
- Your PositiveSSL Wildcard Certificate - ourDomain.crt
- our privKey - priv.key

In wiki tutorial is only used with pem files. if we use our files and rename to pem, it´s doesn´t work. if we refresh browser after changing and 2 commands -> the browser said: load error...and the proxmox interface does not load :(
in console (vms) we have the error:
"Error: TLS handshake failed javax.net.ssl.SSLHandshakeException: java.security.CertificateException: certificate does not match"

on ct´s the console are working fine.

what we can do to use our cert in proxmox https-interface? can you help us please? which file must in which pem file?
very thanks for help.

best regards