If A can't talk to B, and A is perfectly fine, it must be B's fault.  -Clueless in Seattle.
Dear Clueless: Have you considered it might be X, Y, Z, etc. along the way between A and B? Besides, the fact that A can talk to C is not proof that A is perfectly fine.   -Samcelot

I've tried everything and it still doesn't work. Must be your fault! -Confused in Iowa.
You're barely aware of 2% of the potential issues. How could you have tried "everything?" So, shut up and sit down! Let's get to work, shall we?    -Samcelot

For your own sake, stay blissful. Believe me, life is not easy being in the know. Just don't assume, for it makes an ass- out of -u- and -me. The Email Fairy