i found one of the filer is not licensed but still i'm able to access the c$.
Below is the information,i found from the log translator.
An attempt to access CIFS has been denied because CIFS is not licensed on this filer. In general, if CIFS is not licensed then client access of the filer using CIFS is denied. If some other protocols are licensed, then a limited subset of CIFS access is accepted by the filer as part of the support for those protocols. However, if access outside the range of accepted operations is attempted, then this event is generated.
Consider purchasing a license for CIFS protocol support.
Any suggestion, which other protocols supports CIFS access upto limited access.