the error message:

"login failed for login <login name> due to trigger execution."

if I change the trigger (see below) then also I get the login failed error.

create trigger [LoginAudit]

on all server with execute as 'sa'

for logon

as

begin

INSERT INTO Audit_Log

select @@SPID, SYSTEM_USER, HOST_NAME(), HOST_ID(), CURRENT_TIMESTAMP, APP_NAME (), DB_NAME()

END

GO