Hello again, @ruth73.

I appreciate the steps you've tried in importing your invoice. 

Let me help direct you to the right support that can investigate this further in a secure environment. They have the right tools that can help dig deeper why you keep seeing the blank page in the preview section. Here's our direct contact link to connect with one of our QuickBooks Expert: https://quickbooks.intuit.com/community/Getting-Started/Get-help-with-QuickBooks-Online/m-p/185932.

Thank you for your patience. Please visit us again here in the Community if you have other questions about importing forms in QuickBooks. I'm just around the corner if you need help.