Messages giving me network errors

Question

Hi. I'm running Yosemite 10.10.3.
I've recently started using Messages for instant messaging. I have it set up with my Yahoo account, my Google Account, my Facebook account and my AOL account.
Fairly frequently, it will only log into my Yahoo account. When I change my status to Available in the other three accounts, nothing connects but a little tilde-looking character appears for each account. When I click on any of the tildes, I get the following message (this is the example from my Google account):
Messages lost the connection to the Google Talk account “Google”.
A network error occurred
I read a webpage that suggested solving the problem by rebooting my Mac. But it doesn't always seem to work. Today, for instance, I rebooted and nothing changed.
So I'm wondering if there is a way to troubleshoot this problem.
Thanks.

Answer 1

Hi,
Do you use Little Snitch or other software that monitors Ports and IP Addresses Apps are connecting to ?
If not Navigate to ~/Library/Preferences (Hold down the ALT key whilst using the GO menu in the Finder and selecting the Library that appears)
Drag the com.apple.imagent.plist item to the Trash and restart the computer (IMAgent starts up when the computer does)
9:59 pm      Monday; April 20, 2015
​  iMac 2.5Ghz i5 2011 (Mavericks 10.9)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
 Couple of iPhones and an iPad