Identifying a Burned Phone Line
Last updated: April 12, 2026
Last Updated: April 12, 2026
Phone Line Troubleshooting Guide
Overview
A burned phone line is a line that has likely lost trust with recipients because performance on that one line drops meaningfully relative to normal expectations. In practice, customers usually notice it as more pending/failed sends, lower reply rates, or a line that suddenly performs much worse than peer lines.
Common signs
One line suddenly underperforms while your other active lines stay relatively normal.
Messages begin hanging, failing, or getting less engagement than the same workflow normally gets.
You see more blockage-style symptoms after aggressive outreach, repeated follow-up pressure, or poor list quality.
What this does and does not mean
| Situation | What to conclude |
|---|---|
| One or two failed sends | Not enough by itself to call the line burned. Start with normal troubleshooting first. |
| Sharp drop on one line compared with peers | A line-health or reputation issue becomes more likely. |
| All lines are struggling | This may be a broader workflow, content, or account issue instead of one burned line. |
| Customer asks for certainty from one screenshot | Avoid over-calling it. Treat it as a strong signal only after you compare evidence. |
Recommended checks before treating it as a line-health problem
Compare the line against your other active lines over the same period.
Check whether messages are actually failing, pending, or simply not getting replies.
Rule out configuration issues like the wrong from number, bad phone formatting, or a workflow that never fired correctly.
If the symptoms persist on one line while peers stay healthy, gather examples and contact support with the line, timeframe, and recipient examples.
Common false positives
A workflow or CRM issue that prevented messages from reaching Sendblue at all.
A wrong from-number setup or phone-number formatting problem.
A single opted-out contact or isolated recipient issue.
A dashboard visibility delay that made healthy sends look missing.
How to verify it worked after a fix or line change
Watch that line for a fresh test window instead of relying on old failures only.
Compare pending/failure behavior against your other active lines.
Confirm replies and normal conversation activity start returning, not just raw send volume.
If you swapped to a new line, verify the new line performs normally before scaling traffic back up.