The magic bullet for me was putting the SET options within the trigger to bypass any inconsistencies in 3rd party connection drivers.

Try the below and see if it works.

CREATE TRIGGER [DenyUnencryptedConnection]

ON ALL SERVER WITH EXECUTE AS 'DatabaseLogonAuditUser'

FOR LOGON

AS

SET CONCAT_NULL_YIELDS_NULL, ANSI_WARNINGS, ANSI_PADDING ON

BEGIN

DECLARE @LoginNameVARCHAR(128),

@DBNameVARCHAR(128)

SELECT @LoginName = EVENTDATA().value('(/EVENT_INSTANCE/LoginName)[1]', 'nvarchar(128)'),

@DBName = ORIGINAL_DB_NAME ()

IF (SELECT COUNT(ad.DatabaseName)

FROM DatabaseLogonAudit.dbo.AuditDatabase ad

INNER JOIN master.sys.sysprocesses sp on sp.dbid = ad.DatabaseId

INNER JOIN master.sys.dm_exec_connections ec ON ec.session_id= sp.spid

WHERE sp.loginame = @LoginName

AND ad.DatabaseName = @DBName

AND ad.DBLogonAuditRequired = 1

AND ec.Encrypt_option <> 'TRUE') > 0

ROLLBACK;

END;

GO

Regards

Chirag