Urgent! SharePoint site not available

[Haranadh]

Hi,

we have a SharePoint 2013 Farm of 1App , 4 WFE and 1 DB servers.

Suddenly we are unable to browse sites from the one of the WFE server. we are getting below issue while browsing the sites.

The Web application at http://abcdef:6666 could not be found. Verify that you have typed the URL correctly. If the URL should be serving existing content, the system administrator may need to add a new request URL mapping to the intended application.

All the IIS setting are same on the all WFE servers.

 Please let me know if any quick fix to back my sites on the server.

[#2]

Hello!Maybe your hardware crashed, if mapping is getting wrong. All the best! Eva.

[#3]

Thanks for the response, is there a way to check what caused this issue?