BrewPi installation problem - ".... packages cannot be authenticated"

Hi guys…I’m having an issue installing BrewPi on my RPI…see dialogue below…I’ve attempted this a couple of time, rebooted the RPI but I still get the same error…

Any ideas?

I’ve done this successfully prior to today a few times while attempting to diagnose a spurious wifi issue…now just running with hardwired eth0 connection…all of which worked perfectly the last 3 times I’ve tried it…but not today!

sudo ~/brewpi-tools/install.sh

Checking for Internet connection…
Success!

To accept the default answer, just press Enter.
The default is capitalized in a Yes/No question: [Y/n]
or shown between brackets for other questions: [default]

Checking whether this script is up to date…

/home/pi/brewpi-tools is up-to-date.

Disk usage is 44%, free disk space is 3.7G. Enough to install BrewPi

The time is currently set to Mon Jul 13 12:08:52 BST 2015. Is this correct? [Y/n]

*** This script will first ask you where to install the brewpi python scripts and the web interface
Hitting ‘enter’ will accept the default option in [brackets] (recommended).

Any data in the following location will be ERASED during install!
Where would you like to install BrewPi? [/home/brewpi]:
Installing script in /home/brewpi

Any data in the following location will be ERASED during install!
What should be the path to your web directory for brewpi? [/var/www]:
Installing web interface in /var/www

***** Installing/updating required packages… *****

Reading package lists… Done
Building dependency tree
Reading state information… Done
build-essential is already the newest version.
git-core is already the newest version.
The following extra packages will be installed:
apache2-mpm-prefork apache2-utils apache2.2-bin apache2.2-common libapr1 libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap libexpat1-dev libonig2 libqdbm14 libssl-dev libssl-doc lsof
python-pkg-resources python-setuptools python2.6 python2.6-minimal python2.7-dev ssl-cert
Suggested packages:
apache2-doc apache2-suexec apache2-suexec-custom php-pear python-distribute python-distribute-doc python2.6-doc binfmt-support openssl-blacklist
Recommended packages:
python-dev-all
The following NEW packages will be installed:
apache2 apache2-mpm-prefork apache2-utils apache2.2-bin apache2.2-common libapache2-mod-php5 libapr1 libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap libexpat1-dev libonig2 libqdbm14
libssl-dev libssl-doc lsof php5 php5-cgi php5-cli php5-common python-dev python-pip python-pkg-resources python-setuptools python2.6 python2.6-minimal python2.7-dev ssl-cert
0 upgraded, 28 newly installed, 0 to remove and 0 not upgraded.
Need to get 48.5 MB of archives.
After this operation, 93.8 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
lsof php5-common python2.6-minimal python2.6 libapr1 libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap apache2.2-bin apache2-utils apache2.2-common apache2-mpm-prefork apache2 libonig2
libqdbm14 libapache2-mod-php5 libexpat1-dev libssl-dev libssl-doc php5-cgi php5 php5-cli python2.7-dev python-dev python-pkg-resources python-setuptools python-pip ssl-cert
E: There are problems and -y was used without --force-yes

*** ERROR ERROR ERROR ERROR ERROR ***

See above lines for error message
Setup NOT completed

A quick google search let me to this:

It is on an ubuntu forum, but I expect it to work on the pi too.

That seemed to work…thanks Elco…

sudo apt-key update

gpg: key 90FDDD2E: “Mike Thompson (Raspberry Pi Debian armhf ARMv6+VFP) mpthompson@gmail.com” not changed
gpg: Total number processed: 1
gpg: unchanged: 1
Warning: removed keys keyring /usr/share/keyrings/raspbian-archive-removed-keys.gpg missing or not readable