1. How much memory is this host using?
2. Have you disabled tracking on this host?
3. Are you on a 32 Bit BizTalk configuration?
4. Are all the BizTalk SQL jobs running fine?
5. Do you have dedicated tracking host?
6. Do you a seperate host per Adapter type?
7. Is it a heavy message processing scenario when this issue occurs(large messages/many in concurrent messages)?
You are clearly having a memory problem…where in under heavy load this Sendport doesnot have enough resources to complete the operation.
There are many reasons for memory issues.