Email bounce investigation
This guide will help you investigate email bounce issues. It's useful during the email warm-up process and also applicable afterward to address email deliverability problems.
Investigation process
The investigation process consists of these steps:
- Monitor the main indicator = the delivery rate.
- Identify the impacted ISPs and bounce rates.
- Take action.
Delivery rate
The recommended delivery rate during the warm-up is above 99%.
- Delivery rate between 99-98% is OK but requires closer monitoring. If the delivery rate doesn't improve after 3 sends, investigate.
- Delivery rate below 98% needs to be investigated sooner rather than later.
- Delivery rate below 95% requires immediate investigation.
ISPs and bounce analysis
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Go to Overview > My dashboards.
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Click Create new dashoard.
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From the predefined dashboards, select the Email investigation dashboard.
The report provides an overview and trend analysis of each ISP's hard and soft bounce rate evolution over the last 14 days and your overall hard and soft bounce rate. It also allows for monitoring the impact of amendments made after the investigation. You can also find typical benchmarks to compare against for:
- Delivery
- Soft and hard bounce rates
- Click-through rates
- Spam complaint rates
Actions for higher soft_bounce rates
Review the matrix for problem solving.
A. If the soft bounce rate is ISP specific, that is, only 1 ISP is affected, and the soft bounce rate is between 0.5%- 2%
Apply the sending throttling node to the contacts from the affected ISP and extend the sending time to 240 minutes for the next 2 sends. Monitor the soft bounce rate and reevaluate after 2 sends if it drops below 0.5%. If not, prepare a summary of the error codes and messages from the Soft_bounced messages [last 14 days] report in the dashboard and share it with the regional emailing specialist.
Investigate the daily sending volumes and look for potential spikes. If this is the case, there can be temporary damage to your reputation. The sending according to the warm-up plan with consistent frequency and volume, targeting the engaged audience should fix the issues.
B. If the high soft bounce rate is non-ISP specific, that is, multiple ISPs are affected, but the soft_bounce rate is lower than 2%.
Apply the sending throttling node to the next 2 sendings and extend the sending time to 240 minutes. Then, monitor the soft bounce rate and reevaluate after 1 sending if the `soft_bounce rate dropped below 0.5%. If this isn't the case, prepare a summary of the error codes and messages from the Soft_bounced messages [last 14 days] report in the dashboard and share it with the regional emailing specialist.
Also investigate the daily sending volumes and look for potential spikes. If this is the case, there can be temporary damage to the reputation. The sending according to the warm-up plan with consistent frequency and volume, targeting the engaged audience should fix the issues.
C. If the high soft bounce rate is above 2% for one or multiple ISPs.
Prepare a summary of the error codes and messages from the Soft_bounced messages [last 14 days] in the dashboard report and share it with the regional emailing specialist.
Error codes and actions
These are specific error codes from the Soft_bounced messages [last 48 hours] report that needs litigation or further investigation with one of our emailing specialists.
| Error code | Action |
|---|---|
| Banned sending IP [xxx.xx.xx.xx] | IP needs to be removed from the blocklist. Contact the regional deliverability specialists or your CSM. |
| Too old | Usually, Microsoft contacts are impacted by IP reputation. Contact the regional emailing specialists. This message means there were 8 attempts to deliver an email across 8+ hours, with no response. A shared IP with a good reputation might be needed or a further throttling for the Microsoft contacts. Same principle applies for other providers, even though less likely to be the issue. |
| Server temporarily unavailable | No action is needed. |
| The email account you’re trying to reach is disabled | No action is needed. Subscriber is automatically suppressed for future sends. |
| Message rejected due to possible spam content | Review campaign visuals, such as text-to-image ratio or keywords in your content. |
| Mailbox full | No action is required. However, if you are experiencing serious or long-term deliverability issues, we recommend suppressing these contacts for 14 days after the first soft bounce. |
| Account is full (quota exceeded) | No action is required. However, if you are experiencing serious or long-term deliverability issues, we recommend suppressing these contacts for 14 days after the first soft bounce needed. |
| SPF check failed, SPF policy rejection, SPF sender invalid | Sender Policy Framework (SPF) domain records were amended. Contact the regional emailing specialist or your CSM. |
Actions for higher hard_bounce rates
See the matrix for problem solving:
A. If the hard bounce rate is 0.5-1% and only 1 ISP is affected.
Monitor the performance and the hard_bounce rate over the next 1 sending day. It’s possibly a result of adding new audiences with email addresses that aren't valid anymore. If the mail validation was completed and/or the hard bounce rate will not drop below 0.5%, prepare a summary of the errors from the Hard_bounced messages [last 14 days] report in the Warm-up use case and share it with the regional emailing specialist.
B. If the hard bounce rate exceeds 1.5% and only 1 ISP is affected.
Prepare a summary of the errors from the Hard_bounced messages [last 14 days] report in the dashboard and share it with the regional emailing specialist or your CSM.
C. If the hard bounce rate is higher than 0.5% and multiple ISPs are affected.
The domain or IP reputation may be at risk. Prepare a summary of the errors from the Hard_bounced messages [last 14 days] report in the Dashboard and share it with the regional emailing specialist or your CSM.
Updated 1 day ago