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Delivery Alerts

  • When does Plivo determine that my inbound delivery rates are low?

    Our monitoring systems continuously assess the delivery rate of inbound messages. We evaluate the delivery rates of all inbound messages received for your account within the past hour. This evaluation occurs in 15-minute intervals. An alert is triggered if the percentage of undelivered messages exceeds a threshold. This threshold is determined based on your account's past inbound delivery rates.

    For example: 

    • At 11 a.m., we will evaluate the delivery rate of inbound messages received between 10:00 a.m. and 11:00 a.m.
    • If the delivery rate falls below 90% (a threshold determined by the account's previous delivery rates), we will send an alert to your configured email address.

    Note: For inbound messages, the validity of an evaluation period is assessed only if at least 10 inbound messages were processed during that hour. If the number of messages is fewer than 10, no email alerts will be triggered.

  • I've received an inbound delivery email alert from Plivo. What should I do?

    This email is triggered when Plivo’s message delivery monitoring systems observe a significant drop in your inbound message delivery rate.

    A drop in inbound message delivery rate may be caused by any of the following reasons:

    1. An incorrect message URL configured in your Plivo Application
    2. An unresponsive message URL
    3. The message URL takes more than five seconds to respond to an HTTP request
  • I've received an outbound delivery email alert from Plivo. What should I do?

    These alerts are triggered when our message delivery monitoring systems detect a significant drop in your outbound message delivery rate. The email includes the following information.

    1. The total number of outbound messages sent in the past hour
    2. The Plivo Auth ID and account name associated with the messages
    3. The destination country of the messages
    4. The total number of undelivered messages in the past hour
    5. The number of undelivered messages grouped by Plivo error code

    The error codes will indicate how to resolve deliverability issues.

  • Will I start receiving multiple email messages if I enable inbound and outbound message delivery alerts?

    Outbound delivery alerts are sent a maximum of once per day per destination country. For inbound delivery alerts, you will receive at most one email alert daily if there is an issue with your inbound messaging URL. 

    Note: An email alert is triggered only when a significant drop in your inbound or outbound message delivery rate is observed.

  • How does Plivo determine that my outbound delivery rates are low?

    Plivo's alert system monitors critical error codes and generates alerts if there's a dip in the successful delivery of messages to a particular destination. Refer to our troubleshooting guide for more information related to a particular error code (such as 30, 40, 160, etc.). Every 15 minutes, we compare the delivery rates over the previous 60 minutes to  the average delivery rate over the previous seven days. We will email you if we  detect significant variance.

    Here are examples of alert messages. 

    • At 13:00 on January 10, 2021, our systems assessed the delivery rate for messages processed from 12:00 to 13:00 on the same day towards the US. Let's say the calculated delivery rate is 70%.
    • This rate is then compared with the average delivery rates towards the US over the past seven days (January 4 to 10), for the 12:00 to 13:00 time period each day. Assume the average delivery rate from these data points is 95%.
    • The observed drop in delivery rate to 70% represents a significant decrease of 26.3%. If this reduction is attributed to the error codes monitored by Plivo, it would trigger a delivery degradation alert to the designated email address.

    Note: For outbound messages, an evaluation period is considered valid only if there are at least 100 outbound messages to a destination country.

    These alerts help you take immediate action to remedy any issues that may cause your messages to go undelivered.

  • Will Plivo send me an alert when my inbound message URL is unresponsive?

    Plivo’s systems don't perform health checks on inbound message URLs, but they do monitor inbound message delivery rates. If your inbound message URL is unresponsive, we'll see a drop in inbound message delivery rate. You can enable SMS delivery alerts for your account to receive email whenever we observe a drop in your inbound delivery rates. Enable delivery alerts from the console at Messaging > Alerts.

  • Can I receive email alerts whenever there's a significant drop in the delivery rates of my outbound or inbound messages?

    Go to Messaging > Alerts to configure email alerts for your account. When you enable alerts for your account, Plivo will send you email whenever our delivery rate monitoring systems observe a significant drop in your outbound and/or inbound message delivery rates.

  • Why did my outbound SMS delivery fail?

    Plivo sends SMS status codes at each stage of the delivery process. Depending on the message_state returned, we may also provide an accompanying error_code. For example, if delivery is unsuccessful when we try to deliver an SMS message to the carrier, the message_state will be updated from “queued” to “failed” and an accompanying error_code will be given.

    If a message is successfully sent to the carrier, it can still hit roadblocks that cause it to fail. If the message_state changes from “queued” to “sent” and then to “undelivered,” we'll generate an error_code to help you learn more about a delivery issue. 

    This illustration shows a successful delivery path and the message_states that can occur.


    See the list of Plivo error codes for outgoing and incoming messages. 

  • Will Plivo retry callbacks if the message_url is not reachable?

    Yes. If the message_url for your Plivo application returns a non-2xx HTTP status code, Plivo will retry the request to the message_url. 

    Plivo will make a maximum of three retry attempts:

    • The first retry attempt will be made 60 seconds after the original attempt.
    • The second retry attempt will be made 120 seconds after the first retry attempt.
    • The third retry attempt will be made 240 seconds after the second retry attempt.

    Retry attempts are made for both inbound messages and status update callbacks for outbound messages.

    Please note that Plivo expects your server to respond to our requests within eight seconds. Requests are timed out if an HTTP response is not received within eight seconds. Timed out requests are retried based on the retry schedule described above. 

    For incoming messages, you can set the message_url for your Plivo application using our API or in the Applications tab of the user dashboard. For outgoing messages, you can set the message_url in your API code by adding the parameter "URL" = "".

  • What are the different SMS statuses in Plivo?

    Outbound messages

    Your outbound message could be listed as queued, sent, failed, delivered, or undelivered.

    • All outbound messages are initially queued as Plivo accepts the message and attempts to send it to a carrier.
    • A message is marked as failed if an internal error occurs before the message is passed on to downstream carriers. Users are not charged for failed messages. 
    • A message is marked as sent when the message is successfully passed on to a downstream carrier. Users are charged for sent messages.
    • A message is marked delivered or undelivered based on the delivery receipt received from the carrier. Users are charged for these messages.

    Note that delivery receipts are not universally supported across countries, number types, or mobile networks. The final status of a message may remain “sent” in cases where delivery receipts are not received. Delivery reports are not supported in the US and Canada due to federal regulations, so it's always good to consider sent + delivered as delivered.

    Inbound messages

    Your inbound message could be categorized as received, delivered, or undelivered.

    • All inbound messages are initially marked as received
    • If the Plivo phone number that received the message is associated with an application, and the application has a valid message_url configured, then the message will be forwarded to that URL. The message will be marked as delivered following a successful response from the message_url; otherwise, it will be marked as undelivered.