GSM CALL BLOCK ISSUE T-303 expiry, no MM connection available

[Rf Engr.1234]

Can any one tell whats the reason of Blocked Call, tems events show below message,



Block type: T-303 expiry, no MM connection available

what does that mean ??

[buptwzz]

the MS do not receive sig:CALL PROCEEDING after sending sig:CM SERV REQ。check A interface weather BSC has send L3 message to MSC or has received return from MSC.