This may be due to a service endpoint binding not using the HTTP protocol. This may also be due to the server aborting the HTTP request context

A very simple WCF report this exception, only to find that the response class cannot be serialized

Because there is an enumeration statustype in the response class, and the enumeration value of the system is from 0-5, but the database has more than one record with a value of 6

So serialization fails.

Solutions

1. Delete illegal values for the database

2.Response without enumeration, modified to int type

This may be due to a service endpoint binding not using the HTTP protocol. This may also be due to the server aborting the HTTP request context