Start a SQL Trace and add SQL:Stmt Started and SQL:Stmt Completed

or Batch Started and Batch Completed parameters.

use 'All Suppliers' if its a static and use [All Suppliers] if its a column name

Instead of writing

SET ANSI_NULLS ON

write

SET ANSI_NULLS OFF

Can you write here the syntax that you wrote for creating TCP endpoints and for granting CONNECT permission?

Did you create TCP endpoints on Principal and on Mirror Server and then did you give CONNECT permission on both server?

You have to create TCP endpoints on Primary and on Mirror server and then you have to grant connect permission on both servers.

Create TCP endpoints using T-SQL statements and then grant CONNECT permissions to your login on both principal and mirror servers.

CREATE ENDPOINT [Mirroring]

STATE=STARTED

AS TCP (LISTENER_PORT=1430,LISTENER_IP=ALL)

FOR DATA_MIRRORING (ROLE=PARTNER,AUTHENTICATION=WINDOWS NEGOTIATE,ENCRYPTION=REQUIRED ALGORITHM RC4)

Create endpoint...

have you created proper tcp endpoints ?