I remedied a similar problem with Verizon by reinstalling the applicable OS X Combo updater. (I note that the problem recurred and that I had to reapply the Combo several times over a period of time before it was remedied for good.)

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire