T4xG VPN to Watchguard

[HiBit]

Hello,

did anyone get theese devices connected?
I tried several settings in the box, but unfortunately
I didn't get a connection from a T42G or T46G to my
XTM Watchguard (Version 11.9.4 )

I saw several error messages:

TLS Error: TLS handshake failed

TLS Error: TLS object -> incoming plaintext read error

TLS_ERROR: BIO read tls_read_plaintext error: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

VERIFY nsCertType ERROR: /O=WatchGuard_Technologies/OU=Fireware/CN=Fireware_SSLVPN_Server, require nsCertType=SERVER

VERIFY OK: depth=1, /O=WatchGuard_Technologies/OU=Fireware/CN=Fireware_SSLVPN__SN_V1C5000000000_2014-04-06_16:16:09_GMT__CA

TLS: Initial packet from 1.2.3.4:444, sid=c85c67bc fadb0671

TCPv4_CLIENT link remote: 1.2.3.4:444

TCPv4_CLIENT link local: [undef]

TCP connection established with 1.2.3.4:444

(I changed the correct IP above)

Any suggestions to get it working?