Things to try if you are having problems

[gvmax]

Try unlocking captchas
https://www.google.com/accounts/UnlockCaptcha

[Robert]

I am receiving the texts, but I can't send any replies through the client.  I tried unlocking the CAPATCHA's, but I'm still not having any luck.. (btw, the link isn't working)  Any other suggestions?

[xur17]

I'm having this same issue. I am unable to reply to messages using a gtalk account. I am using 2-factor authentication if that matters.