Were sorry, QuickBooks encountered an error while calculating tax. Try reselecting the tax rate or reentering the product/service item and saving the form again.

I figured out what the issue is. I give my clients a discount on my products & what is happening is the HST is calculating over the entirety of the invoice like it should but it isn't rounding properly. I noticed it when the HST was calculating out to .5747 which should round down 0.57 but it was rounding up to 0.58 causing it to throw an error. At least that's what I think is the issue, all I had to do to fix it was change the HST manually to the correct amount regardless if it calculated it correct or not because it still throws the error sometimes when the HST is calculated correctly.

Hi there. Thanks for reaching out in the Community. I'll be happy to guide you along the right path for achieving your QuickBooks goals. You may be experiencing the rounding off of numbers in QuickBooks. The program automatically does the rounding by two decimal places. I encourage you to check out this helpful article that explains more about how rounding works in QuickBooks: Tax Rounding off logic in QuickBooks Online API.

Let me know if this explanation helps bring things into perspective. I'll be a message away.