browser showing "the connection timeout " during preview

Hello

This error may occur in different condition , are listed below :

1 - May be your connection to database timed out , so you can increase connection timeout in we.config file

2 - Problem of session expiry , make sure session duration in web.config

For that find in web.config file and increase session duration

3 - If you have used any than you need to increase time out

For more reference you can go through forums :

https://stackoverflow.com/questions/4308417/connection-timeout-for-sql-server

https://forums.asp.net/t/1389167.aspx?How+to+set+timeout+property+to+Connection+String+in+web+Config+

https://www.codeproject.com/Questions/251037/Connection-TimeOut-Expires-in-ASP-Net

Thanks