importance of authentication data

Hi gurus,

can you please explain me the importance of the authenitication data in the Communication channel.

I am talking about the communication channel ---> that is available for the Business systems in the integration builder.

what will happen if this data is not maintained.

I have one SRM system maintained in the XI ---> with communication channel being ---> GeneratedReceiverChannel_XI

will the authentication data be used by the XI to commuincate with SRM.

Please help me out , i have done all the required settings but still end up getting the message ---> in SXMB_MONI on SRM System.

is this message because of the above setting?

<SAP:Category>XIServer</SAP:Category>

<SAP:Code area="INTERNAL">CLIENT_RECEIVE_FAILED</SAP:Code>

<SAP:P1>400</SAP:P1>

<SAP:P2>ICM_HTTP_CONNECTION_FAILED</SAP:P2>