Hi benedict2,

Thank you for letting us know about the error you received, so we can help you resolve it.

Yes, the "Unexpected Error (-37100)" on mobile apps was reported last month, and we found out that it's triggered when the old GST code is used. The good thing is our engineers have already created a fix for it. All you need to do is update your QBO mobile app, and you should be able to create expenses without errors. However, it sounds like you're able to create expenses now. Can you please confirm it?

Please know that you can also sign in to your QBO company using a mobile browser in case there's an unusual behavior on the app. However, you'll want to report any issues to us here immediately so we can address them as soon as possible.

On the other hand, errors and unusual behaviors are sometimes caused by compatibility issues. I'm sharing this article which contains information about the recommended operating system's version and browser: QuickBooks Online access for mobile devices.

I'm just right here if you have any other concerns with about your QuickBooks app.