QB Issue Resolution:

There appear to be a couple of problems with 2019.  See if either of these helps.

https://community.intuit.com/questions/1779142-why-can-t-i-activate-my-qb-2019-accountant

https://community.intuit.com/questions/1779087-can-t-open-quickbook-2019-after-successful-install

Resolution for Issue 'quickbooks 2019 wont register' available: Yes (Solved).
Source: Intuit Community forum.

quickbooks 2019 wont register: 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.

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