SQLServer.in

This error could be due to the logon trigger in sql server 2005, like the one mentioned in the below link

http://www.mssqltips.com/tip.asp?tip=1830.

Solution

There are only two ways to connect to sql server in this scenario.

1. Connect using DAC.(using -A)

sqlcmd -S LocalHost -d master -A
go
drop trigger trigger_name on all server
go

2. Connect using sqlservr.exe from the binn folder

Execute the sqlservr.exe from the command prompt, specifying the location of the binn, using -m & -f to start sql in single user mode with minimal configuration.

Logon failed for login due to trigger execution

Once SQL is started with minimal config, you could connect through management studio & disable the trigger.