Thanks for reaching out to us in the Community. I'm to share some information about the issue you're getting when accessing sales tax center in QuickBooks Online (QBO).
We have received reports regarding customers unable to access the sales tax center in QBO. Our Product Engineers are now working hard to investigate the cause and come up with a solution as soon as possible.
While we don't have a firm timeline for when this will be resolved, I highly suggest contacting our Phone Support team so they can add you to the list of affected users. Once added, you'll receive an email notification once the investigation is done with a resolution. I'll also update you in this post as well.
Here's how to reach them:
1. Click the Help icon (question mark icon) at the top right of your QBO account. 2. Select Contact us to connect with a live support agent.
Please let me know how it goes after contacting them. I'm only a few clicks away should you have any other questions or concerns. Take care and have a great rest of the day!