We are using AX 2009 Business connector for our .net application to get the data from AX.once in a week or month it is not able to connect AX using business connector in production environment. Below is the error logs we found during the connectivity issue. Error log "2018-09-05 19:01:51,019 [56] ERROR Instrumentation.Logging.Logger AX Microsoft.Dynamics.BusinessConnectorNet.LogonFailedException: You are not a recognized user of Microsoft Dynamics AX. Contact your system administrator for help."
and event viewer log as below "Unable to connect to an Application Object Server. A server name may not be specified correctly in the client configuration, or the server specified may not be available."
After restarting Application pool our application is working fine . Can any one help me why it is happening.