Instead of resolving for:
it was resolving for:
Nice, isn't it?
I've been seeing these errors, esporadically for a few days but never discovered where is wass the error until a few minutes ago suddenly the words "DNS poisening" came to my mind....
And, I just had to increase the version number on the SOA of the domain and restart the master and slave DNS servers.
In fact, things are normaly easy to solve AFTER one understands the cause of the problem!