WHMCS Tags troubleshooting-article Troubleshoot and resolve issues with DUPLICATE_INVOICE_ID errors. Troubleshoot and resolve issues with DirectAdmin sending piped email replies twice. Troubleshoot and resolve duplicate system themes appearing in the System Theme menu. Troubleshoot and resolve The system blocked a potential email loop. (WHMCS 8.4 and later) or Blocked Potential Email Loop (WHMCS 8.3 and earlier) errors. Troubleshoot and resolve empty pages while using WHMCS. Troubleshoot and resolve issues with Enom Portal type is not allowed errors while using the eNom New TLDs addon module. Troubleshoot and resolve issues with User not permitted errors while using the eNom New TLDs addon module.