A connection was successfully established with the server, but then an error occurred during the pre-login handshake
Solution
1) Clean your VS.Net Solution
2) Rebuild Project.
3) Reset IIS
4) Run the project again.
Basically that solved my problem, but in my case i was not getting this error and suddenly my local environment starts giving me above error, so may be that trick work for me.
- Save your work,
- Close Visual Studio, then
- Re-open your project
This worked for me.
In my case this error occurred with dot net core and Microsoft.Data.SqlClient.The solution was to add ;TrustServerCertificate=true to the end of the connection string.