Support & Troubleshooting

Resolving common
issues

Abnormally low response rates, undelivered emails, missing data, import errors — the most frequent causes and their immediate solutions.

8 min read
EC
Comulead Team
March 2026
Technical troubleshooting

Issue 1 — Survey emails are not received

This is the most common issue. Before contacting support, check these causes in order:

1
Check the send status in Cortex Voice

Surveys → select the survey → Send Metrics tab. Check the Status column for each contact. Possible statuses are: Sent, Opened, Soft Bounce, Hard Bounce, Suppressed. A Suppressed status means the contact was on the suppression list before the send.

2
Check the recipient's spam folder

Ask the recipient to check their junk/spam folder. If the survey is there, ask them to mark the sender as Safe or add it to their contacts. Long-term, configure the SPF and DKIM records for your sending domain (see the Technical Troubleshooting section).

3
Check the email address in the CSV

A poorly formatted address (extra space, special character, non-existent domain) generates a silent bounce. Check under Contacts → search for the contact → verify the displayed address. Correct it directly in the contact record or via a new CSV import.

Important — Re-sending a survey

Do not resend a survey to the same contact within 90 days if it was successfully delivered. If the suppression rule is active, Cortex Voice will automatically block sends that are too close together — this is intended behaviour, not a bug.

Issue 2 — Response rate is very low (< 10%)

Likely causeDiagnosisSolution
Subject line flagged as spamOpen rate < 10%Revise the subject line, remove spam trigger words
Cold contact listContacts inactive for > 6 monthsSegment the list, prioritize recently active contacts
Poor send timingSent Monday AM or Friday PMReschedule to Tuesday–Wednesday, 10 AM–2 PM
Survey too longMore than 3 questionsReduce to the Standard template (2 questions)
Unknown senderNo first name in the subjectAdd a firstname column to the CSV

Issue 3 — Error during CSV import

1
Error: "Email column not found"

The email column header must be exactly email (lowercase, no accents, no spaces). Check that there is no invisible space at the beginning or end of the cell. Open the CSV in a text editor (Notepad, TextEdit) to inspect the raw headers.

2
Error: "File format not supported"

Cortex Voice only accepts .csv files. Files in .xlsx, .xls or .ods format are not supported. In Excel: File → Save As → CSV UTF-8 (comma-delimited). In Google Sheets: File → Download → Comma-separated values (.csv).

3
Warning: "X invalid addresses ignored"

This message is a warning, not a blocking error — the import still completed for valid addresses. Download the error report (the Download errors button after import) to see the list of rejected addresses and correct them.

Issue 4 — Dashboard data appears incorrect

1
Check the selected time period

The date range filter at the top of the dashboard is remembered between sessions. If you see an unexpected score, check that the period shows All time or the desired range. A filter set to the last 7 days may show a very different score compared to the annual figure.

2
Check that no surveys are excluded from the calculation

Certain archived or Test-flagged surveys are excluded from the global NPS calculation. Under Surveys → filter by Archived status to see if any data is missing. You can unarchive a survey from its context menu.

Tip — Excluding test responses

If you responded to the survey yourself during the testing phase, your response is included in the calculation. To exclude it: Verbatims → find your response → context menu → Mark as test. It will be removed from the NPS calculation immediately.

Key takeaways

Key points
  • Always check the Send Metrics tab before reporting a delivery issue
  • A response rate below 10% generally indicates a subject line, timing or list quality problem
  • The most common CSV errors stem from encoding (ANSI vs UTF-8) or the email column name
  • Check the dashboard date filter before concluding there is a data anomaly
  • Mark your test responses to exclude them from the NPS calculation
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