QuickBooks Error 6123 is a common issue that occurs when opening a company file or while upgrading it. It can be caused by network connection problems, damaged company files, or firewall settings. Resolving this error may involve troubleshooting network issues, repairing QuickBooks installation, or restoring a backup file.

<a href="https://www.quickbooksupportnet.com/how-to-resolve-quickbooks-error-6123/">QuickBooks Error 6123</a>