Hello @keeslamper,
Could you give us some context as to what happened before this?
You could install our free Number Tools extension to see what’s going on with the numbers.

Hey @dpeyou,
We have done nothing special before the numbering changed. The order numbering was at 1922 and then just randomly reset and started at 1 again.
@keeslamper,
Show us your error logs
Could you share your system report status at WooCommerce > Status > get system report?
Did someone on your site possibly mess with these settings?

@keeslamper,
Do you have the yearly reset option enabled?

As of now I think these are the possible causes:
– Yearly reset was enabled and triggered because an invoice for either last year or next year was created.
– The database table was removed or reset (wp_wcpdf_invoice_number ).
– Someone manually set the next invoice number to 1 (quite unlikely).
@dpeyou,
Yes we had that option enabled. I have disabled that option now so i think this problem has now been solved.
Thanks for the help!