Requested action not taken: mailbox unavailable or not local

Hi Friends,

i have setup exchange 2010 on premise and Recently facing issues regarding email bounce from google App with below error.

Error :

"550 Requested action not taken: mailbox unavailable" only form some of the mail server.
and
"Requested action not taken: mailbox unavailable or not local"

to resolve this issue i search a lot on internet but not able to find any propper solution, after investigation i found the solution and working fine without any problem,

Resolution :

configure Gateway firewall for SMTP Traffic or disable Email scan for Mail server.


in my next blog i will describe various smtp errors with cause and resolutions.

thanks,
Gaurang Patel