Hi Abiose,
Welcome to the Method forum! While you wait for a call from our support team, you may want to try the following.
1. Resetting your password HERE
2. Verify that your are logged into QuickBooks as the admin user
3. Verify the permissions on the QuickBooks certificates for the Method Integration Engine and the Method Listener. These can be located by navigating to Edit > Preferences > Integrated Applications > Company Settings. Removing these will prompt you to re-add them the next time you connect the Method Integration Engine to QuickBooks.
I hope this helps.
--Audisho