Hi Enrique,
An error occurred during a connection to rrhh.unizar.es. Cannot communicate securely with peer: no common encryption algorithm(s). Error code: SSL_ERROR_NO_CYPHER_OVERLAP
If you want to know what's going on: "man crypto-policies".
A ¿workaround? for firefox is execute firefox with "NSS_IGNORE_SYSTEM_POLICY=1" in the environment. You can achieve this creating a bash script named "firefox" in the ~/bin directory.
You can create the file easily if copy&paste all-in-one this text in a terminal window:
#====8<----- copy from here...
mkdir ~/bin
cat > ~/bin/firefox <<EOF #!/bin/bash
env NSS_IGNORE_SYSTEM_POLICY=1 /usr/bin/firefox "$@"
EOF
chmod +x ~/bin/firefox
#====8<----- to here...
Regards, Fernando.