Create an invoice with the right number you want, click save and new.  That should re-start the invoice numbering.

Resolution for 'automated invoice issue: 'Invoice numbers are not synchronized anymore. I’d like to set the initial invoice number for automated invoice numbers.' available: Yes.

The automated invoice issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the automated invoice issue yourself by looking for a resolution described in the article. If it is a complex automated invoice issue or you are unable to solve the issue, you may contact us by clicking here or by using other automated invoice support options.

For more information about resolving issues related to automated invoice in Quickbooks/QBO or to get support for the issue 'Invoice numbers are not synchronized anymore. I’d like to set the initial invoice number for automated invoice numbers.', click the link below: