File name maybe incorrect on database path?

Question

Hi Team

 

Please help me to understand this error, the web config has the following connectionString. What does this error mean? Do i have to change the path..? 

<connectionStrings>
    <add name = "eNtsaOnlineRegistrationDB" connectionString = "Data Source=GcobaniM-L\SQLEXPRESS;AttachDbFilename=[DataDirectory]\eNtsaOnlineRegistrationDB.mdf;Initial Catalog=eNtsaOnlineRegistration; Integrated Security=True" providerName="System.Data.SqlClient"/>
  </connectionStrings>