Server stopped responding

Dear Friends,I have a server running domino 5.0.12 (administration server) which smtp server also. The O/S is windows 2000 advace server. the server stopped responding. when i checked the server console i found the error message keep on displaying “unable to create server task: access to the server is restricted due to max number of users”. why this message comes and how will i solve this when i face this prob next time in future. Pl explain the reason.

thanks in advance.

deepak