How many times have you seen this error?
SQL SERVER DOES NOT EXIST OR ACCESS DENIED
The cause of this error can be different in different cases here are two causes:
1)When specifying connection string please don’t surround server name with curly brackets like this (localhost).
2)Another cause can be Windows firewall which will prevent you from connecting to the database hosted on different server. Here is what you can do.
Start menu -> click on run and type -> wscui.cpl -> Select Exceptions -> Add port ->
Enter Name: SQL SERVER
Port Number 1433
Thanks to Jin for providing me with the second tip!