You can have this error while Open your site at Sharepoint Designer
This means:
- Anonymous authentication is not configured for the problematic web application in IIS
- Server is running out of memory
Fix: Free up memory on the server
How can we free up Memory
Open Task Manager Go Processes You see Sql Servece(sqlservr.exe) use 19 gb ram of your machine that has 20 gb
So we must restart Sql Service
Go Server Manager=>Configuration=>Services=>Find Sql Server(MSSQLSERVER) service (restart it)=>Stop Service=>Start Again
Now You Solve the problem
Open Designer and your Site or collection ...Thats all
