Random ASP.NET 2.0 crashes with MSMQ/NAS and Nav 3.60

We have an application that is an extension of Nav to the web. The system is used for accounting and approval of invoices/credit memos. The app is written in C#, and is run on an IIS webserver. The connection to Nav is via MSMQ and NAS. The web makes a request XML-style to Nav, and gets the result back as an xml message.

The system works fine until it gets under some load (50-100 users). When that happens we get errors in the event viewer like “A field or property with the name X was not found on the selected data source”. This happens with different fields and on different pages, but it is always the same field on a particular page. I e F68 on PurchDoc.aspx, F3 on PurchDocLines.aspx, etc.

When I check the input/output xml messages from Nav theyre completly OK. Something happens on the website when it tries to read the message.

Have anyone experienced or heard of a similar issue?

The thing that seems to have solved the problem was to rewrite the message queue handler in both navision and on the website so that we use correlationid to match request/reply messages.

Earlier we handled message ID’s in an xml-tag in the message.

We managed to get the problem again by doing something as simple as to make a request from web that takes some seconds to complete, and then when the reply is being generated for the first request, we log in as a different user and make a request.

In the version with the old ID-handler, we get field error message. In the new version with correlationid we have to wait until the first request completes, then we get reply for both requests.

The problem was that “the other end” only supported one request at one time (possibly a license issue), and with the old id-handling the messages got mixed up.