unexpected error exception while searching customers

@operator

hi,

I'm trying to search a Customer by SalesOrder number, but I'm getting "An unexpected error occurred.". Order number is ok, I can search by it fine.

What is the reason for the error?

Here is the .net code:

             string Id = "182";              CustomerSearch cs = new CustomerSearch();                          cs.transactionJoin = new TransactionSearchBasic();              cs.transactionJoin.tranId = new SearchStringField();              cs.transactionJoin.tranId.@operator = SearchStringFieldOperator.@is;              cs.transactionJoin.tranId.operatorSpecified = true;              cs.transactionJoin.tranId.searchValue = Id;                SearchResult sr;              sr = nsService.search(cs);