Unable to email to .mobi domains

[David_21114]

This isn't directly related to FIOS, however I'm unable to send email to the .mobi domain.  Verizon reports that the address is not valid. This also occurs when trying to send to the domain from webmail (netmail.verizon.net).   I am using a valid domain name and suffix, as I'm able to send to the .mobi domain from gmail and yahoo without issues.  

Any thoughts Verizon? 

[dslr595148]

What was the exact error message/code?

Sometimes tells me, there is something wrong with there end of the line.