When you use the INFA_CTBlockInputFlow() and INFA_CTUnblockInputFlow() functions in the procedure code, verify the procedure checks whether or not the Integration Service allows the Custom transformation to block incoming data. To do this, check the value of the INFA_CT_TRANS_MAY_BLOCK_DATA propID using the INFA_CTGetInternalPropertyBool() function.
When the value of the INFA_CT_TRANS_MAY_BLOCK_DATA propID is FALSE, the procedure should either not use the blocking functions, or it should return a fatal error and stop the session.
If the procedure code uses the blocking functions when the Integration Service does not allow the Custom transformation to block data, the Integration Service might fail the session.