how to resolve Timeout Expired Error

Hi friends,

 

Our application(Asp.Net Core) and SQL Database are there in the aws server.Before it is working perfectly but some times it is showing the following error.

 

Error :

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

I don't changed anything in the code.Why it is showing this error?

 

Please suggest me to fix this one.

 

Thanks in Advance.