Debug a VB.net project

Job ID: 36000009

Budget: $30 – $250 AUD

Hi Freelancers,
I have an existing VB.net project developed by another Freelancer which I need some help with. The app uses the Xero API to download a CSV summary of the account's invoices at regular intervals. It appears to work fine, but after about 90 minutes it requests that the user logs in again. The app should request refresh tokens as required from the Xero API but appears to be failing to do so. Please see the attached files for source code.

I'm hoping for a quick turnaround on this project, and I'm hoping for a simple fix for this project. I will be prioritising working with Freelancers who can deliver this quickly.
Related categories: PHP Visual Basic .NET Software Architecture VB.NET