Error: 'There was a problem connecting to the CUPS server.'after upgrade 14.04 to 14.10
Solution 1:
List the iptable configuration with the command
sudo iptables -L
Then use the following script to open CUPS connection on the port 631
## open cups (printing service) udp/tcp port 631 for LAN users ##
iptables -A INPUT -s 192.168.1.0/24 -p udp -m udp --dport 631 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -p tcp -m tcp --dport 631 -j ACCEPT
Allow all inbound cups requests.
iptables -A INPUT -p tcp --destination-port 631 -m state --state NEW -j ACCEPT
iptables -A INPUT -p udp --destination-port 631 -m state --state NEW -j ACCEPT
Hope this helps!
Solution 2:
I had a problem very similar to yours: I had configured in my computer a remote printer and it worked in Ubuntu 14.04. It stopped working after the upgrade to Ubuntu 14.10. Trying to view its properties resulted in the message "There was a problem connecting to the CUPS server". The printer could be seen in localhost:631 but here we have a difference: I told it to print a test page and there was no error message; later I went to the printer and the test page was there.
And in my case, I then just removed and re-installed the printer, and then I was able to print to it.
So if anyone else has this problem, please start by removing and re-installing the printer.