There are several issues with TLS connections and the F5 firewall, and that looks like the case. That firewall terminates a TLS session if the client hello is between 256 and 512 bytes. If that is the case you can verify using wireshark.
The solution we adopted in later versions of gnutls is to add padding: https://gitlab.com/gnutls/gnutls/commit/b6d29bb1737f96ac44a8ef9cc9fe7f9837e20465
There are several issues with TLS connections and the F5 firewall, and that looks like the case. That firewall terminates a TLS session if the client hello is between 256 and 512 bytes. If that is the case you can verify using wireshark.
The solution we adopted in later versions of gnutls is to add padding: /gitlab. com/gnutls/ gnutls/ commit/ b6d29bb1737f96a c44a8ef9cc9fe7f 9837e20465
https:/