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

Hi there, thanks for joining the Community

We're aware of reports of this error for iOS users and this is currently being investigated by our team. 

We'll keep you informed about the progress of the investigation through regular updates; the next update is scheduled for 18 July, 24. 

Thanks for reaching Intuit support. I'm just a post away if you have further questions or require additional assistance