404 file not not found- sharepoint server

[Corpo185]

I had created a site in my company's private group. It's existed for months but when i was going to the document library after i save a file all of a sudden, it said i don’t have an access to this page but now the entire site is gone and replaced by a 404 Not Found error.What happen to my site?...is there anything that i can do to recover that site cus all of my work related file are store in that site.

[#2]

You can see if the site collection was deleted and use Get-SPDeletedSite/Restore-SPDeletedSite. Otherwise, you can grab a copy of your content database backup and restore the site.
https://docs.microsoft.com/en-us/powershell/module/sharepoint-server/get-spdeletedsite?view=sharepoi...
https://docs.microsoft.com/en-us/powershell/module/sharepoint-server/restore-spdeletedsite?view=shar...
https://docs.microsoft.com/en-us/SharePoint/administration/restore-a-content-database
https://docs.microsoft.com/en-us/SharePoint/administration/restore-content-from-an-unattached-conten...