Can't find a certain invoice

i am using the invoice ninja about 2 years and everything goes well. BUT i need to find the invoice no.15 and it is not anywhere ! If i search one by one or through searching topic the result is 0.
When i go to create a new invoice with no.15 it says that the invoice exists !

Any idea what’s going on?

Thanks !

Is it self-hosted? Check the DB!

Yes, i found it. It has checked the deleted trigger.
Thanks !