QB Issue Resolution:

You will need you QuickBooks license number handy then follow the steps below:

Go to Help menu.
Select About QuickBooks.(last option)
Once you have the QuickBooks window, press CTRL+R+P all together and Register QuickBooks Now window will open up and it will have your license number and product code there.
It will now ask you for a validation code,if you do not have one then call this number to get a validation code — 1-800-488-7330 Open: 6AM-6PM (PST) Mon-Fri, 6AM-3PM (PST) Sat

Resolution for Issue 'How do I re-register 2012 QuickBooks Pro?' available: Yes (Solved).
Source: Intuit Community forum.

How do I re-register 2012 QuickBooks Pro?: this 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 issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for 2012
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Error Recovery for 2012 [Canada]
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