QB Issue Resolution:

Please try again after updating the Sync Manager version by selecting the QuickBooks -> Help Menu -> Update QuickBooks option.

Resolution for Issue 'Syncing problem: Error msg: unable to communicate with sync manager.' available: Yes (Solved).
Source: Intuit Community forum.

Syncing problem: Error msg: unable to communicate with sync manager.: 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 communicate
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Error Recovery for communicate [Canada]
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