QB Issue Resolution:

Try quitting the server and relaunching it. Then choose Check for Updates. Does it report a new version?

Resolution for Issue 'Unable to update Quickbooks 2016 Server (for Mac OS).' available: Yes (Solved).
Source: Intuit Community forum.

Unable to update Quickbooks 2016 Server (for Mac OS).: 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 Check for Updates
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Error Recovery for Check for Updates [Canada]
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