sudo add-apt-repository ppa:ubuntu-mozilla-daily/ppa
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv B34505EA326FEAEA07E3618DEF4186FE247510BE
gpg: requesting key 247510BE from hkp server keyserver.ubuntu.com
gpgkeys: HTTP fetch error 7: couldn't connect to host
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0
then you download the key manually from the website and add it to ubuntu. Go to anonymouse.org and visit http://keyserver.ubuntu.com:11371 through the proxy site
Search for the corresponding key on the server as 0x247510BE and download the key, and save it to a text file on local system
Key should be something like below
-----BEGIN PGP PUBLIC KEY BLOCK----- Version: SKS 1.0.10 mI0ESYo68wEEAKSgKJImCQIcSP/b+24TS0NYzxpf5Y34WOfQBaGpTVhkSXx2TCcF+kC0P3zz wAsrvL8AULpr2Ww33ahnQ7Cg3kzBxTneo6jdvQOBwshSHMey/PhBAu0ew9zrt/OuKToMJY2h 0TRA2EG6OfcTA8LOm1wkWWadTUG+fqduKKeHDmjdABEBAAG0MUxhdW5jaHBhZCBQUEEgZm9y IFVidW50dSBNb3ppbGxhIERhaWx5IEJ1aWxkIFRlYW2IXgQQEQgABgUCTSOx/wAKCRD8kg8z /8ZzxIhpAP9ECWs+m6W/QRysu9APd93yPic08GnN82XFZ/6Zf8oXrgEAruIdOrqeWzvqv1OT pFo/9ApgjkG98wSSk5AsL5RDHvKItgQTAQIAIAUCSYo68wIbAwYLCQgHAwIEFQIIAwQWAgMB Ah4BAheAAAoJEO9Bhv4kdRC+2KED/3F9TudOsjvGfeIevqUsOXocd3CQTGJMGu3YevuiBk+l rGj0EHi9MZ7yq3vi4ZVFoFairUhedQ6iuLrug301CkVNKSYwhwQzQRVkG0b8XqIAqg2UKlPe JD6nYoEncZNZkD0RHLDAM3Ii/PN1znMKyRZfWKI7MY1IPbECFXFQTv6I =exAf -----END PGP PUBLIC KEY BLOCK-----
Then add the key to ubuntu using 'sudo apt-key add ' and then run 'sudo apt-get update' to update the repository which should accept the key
