Can't backup company file - "Quickbooks couldn't open your company file"

I have not been able to perform a local backup for the past couple of weeks. I'm running Quickbooks Desktop Pro 2018. When I initiate the local backup, it starts with a verify date intergrity check, which fails and I get a message that "Quickbooks could not open your company file". The message also states that if the problem continues to report error codes -6143, -101 to customer support. I have tried using the QB doctor appl to fix it. It even ran all night, and accomplished nothing. I have tried to research these error codes online. These codes do not come up in my searches. I have tried the QB utilities to fix the issue, which has been unsuccessful. I have upgraded to the current version of Quickbooks and Windows 10, which also did not fix the issue. I am hesitant to enter any more activity into our Quickbooks software until this issue is resolved. I fear having to re-enter activity since my prior successful backup on 4/8/2019. Does someone know how to fix this issue? Thanks!