Need ASP.NET App synced with Quickbooks desktop to support multiple users.

Project Budget (USD)

Project Description:
I already have the ASP.NET app built and synced with Quickbooks but it will not support more than 1 user. I need about 6 to 8 users at once to use it. I can't figure out how to do it. I used the 3way auth setup.
I can give file source access if needed before deciding on the finial cost. I can also send you a link with login to the current working app.
I have a some other small changes as well but I want to make sure this is something you are able to fix first.

Skills required:
.NET, Quickbooks & Quicken
Project offered by: