HTML5 VPN Portal - ssl_error_no_cipher_overlap

Hello all,

I'm having a very simple configuration which seems not to work 

UTM9, Home Edition license, in HTML5 VPN Portal I define a new connection, HTTPS to one of my server (simple Apache server). When I try to access the link from the VPN Portal I receive an error containing "ssl_error_no_cypher_overlap".

I know the error, is a mismatch in SSL suit and means the UTM and the backend Apache server cannot find a common encryption algorithm.

When I access the Apache server directly, I get the connection encrypted with TLS1.3 and TLS_AES_128_GCM_SHA256

When I access the VPN portal, I see TLS1.2 and TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 cipher suite.

I tried to force the Apache server with TLS1.2 but still doesn't work.

What am I missing here? Any advice is appreciated.

Thanks!