Rejected extension not found

plz help me my asterisk 1.4.22 fedora 8 server regesters eyebeam clients but the clients are not able to establish calls
call failed:not found message is displayed on client phones while
chan_sip.c 14035 handle_request_invite rejected because extension not found
message is displayed on asterisk server.
ready your username is … is displayed on softphone but still no communication.
what to do please help.

Fix the dial plan, or at least post the dialpland and verbose CLI for a failed call, here.

plot your extensions.conf, and your sip.conf here.
this error usually happen either because you are using different context for the sip user, or the extension doesn’t exist extensions.conf

thanks to all for support i hve successfully fixd it there were some grammatical mistakes in conf files now every thing is but two clients can have voicemails but one client do not have any voicemail functionality
can any one suggest any thing