MySQL会话状态提供程序在过期的会话上崩溃

I have a site running in IIS 7.5 ASP.NET 4 using MySQL Connector 6.7.4, I am trying to set it up to store session state in my database. It works fine to start with (I can store the state). But when I leave my browser open for a long time and then tries to refresh a page I get the following error:I have a site running in IIS 7.5 ASP.NET 4 usin