> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rootly.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Communication Sources

> Configure the email addresses and phone numbers your incident communications send from, and get them allowlisted before you need them.

A **communication source** is the address or number a message arrives from. Email communications send from addresses you configure; SMS communications send from numbers Rootly provides.

This is the least interesting part of the module and the most common reason a communication fails. A message that is written, reviewed, and sent still fails if the recipient's mail provider quarantines it.

<Warning>
  Allowlist Rootly's sending addresses and numbers as part of setup, not after the first missed update. Filtering is silent — Rootly reports the message as sent, because it was; it simply never reached the inbox.
</Warning>

***

## Email Sources

Email sources are the **from** addresses your communications use. Which address a message arrives from shapes whether it is trusted, read, and replied to correctly.

<ParamField path="From address" type="email">
  What recipients see as the sender. One source is selected as the default for outgoing communications.
</ParamField>

Choosing an address is mostly about the audience:

* **Customer-facing communications** should come from an address customers recognize and could plausibly reply to. An unfamiliar domain mid-incident invites suspicion at exactly the wrong moment.
* **Internal communications** can use a more operational address, since colleagues will recognize it.

<Tip>
  Use an address that is monitored, or one that makes clear it is not. Recipients reply to incident updates — with questions, with impact reports, sometimes with information you need. Replies into an unwatched mailbox are lost signal.
</Tip>

***

## SMS Sources

Rootly provides the phone numbers SMS communications send from. They are listed in the Communications configuration so your team can distribute and allowlist them.

SMS is the highest-attention channel and the least forgiving:

* **It cannot be recalled or corrected.** An email can be followed by a correction that lands in the same thread; an SMS correction is a second alarm.
* **It arrives out of context.** No subject, no thread — just text on a lock screen, often at night.
* **It is length-limited.** Around 160 characters per segment, so it is a pointer rather than a summary.

<Note>
  Reserve SMS for audiences and severities where waking someone is proportionate. An executive group scoped to severity 0 is a good use; a service-team group scoped to any severity will produce fatigue and get muted — after which it carries no signal at all.
</Note>

***

## Getting Rootly Allowlisted

Do this once, ahead of time, with whoever runs your mail and mobile device management:

<Steps>
  <Step title="Collect the addresses and numbers">
    Both are listed in the Communications configuration area.
  </Step>

  <Step title="Allowlist the sending addresses in your mail provider">
    Ask for them to bypass spam filtering and quarantine for internal recipients.
  </Step>

  <Step title="Share the numbers with recipients of SMS communications">
    An unknown number sending an urgent message is exactly what people are trained to ignore. Telling stakeholders in advance which numbers are Rootly's makes the difference.
  </Step>

  <Step title="Send a test to each channel">
    Use a low-severity or test incident and confirm the message arrives in the inbox rather than the spam folder, and that the SMS reaches a real handset.
  </Step>
</Steps>

<Warning>
  Test with a recipient outside your own team. Internal mail between colleagues is filtered far more leniently than mail to a customer's provider, so a successful internal test proves less than it appears to.
</Warning>

***

## Troubleshooting

<AccordionGroup>
  <Accordion title="Recipients say the email never arrived" icon="envelope-circle-check">
    Delivery and receipt are different things. If Rootly reports the message sent, it left successfully — so the problem is downstream. Check the recipient's spam or quarantine folder, confirm the sending address is allowlisted, and ask their mail administrator whether it was filtered.
  </Accordion>

  <Accordion title="Emails arrive in spam for external recipients only" icon="filter-circle-xmark">
    External providers apply stricter filtering than your own. Sending from a domain the recipient recognizes helps most; consult whoever manages your email authentication about the sending domain's reputation.
  </Accordion>

  <Accordion title="SMS messages are not arriving" icon="mobile-screen">
    Confirm the recipient's number is correct and reachable internationally if they are outside your usual region, and check whether their carrier or device is blocking unknown numbers. Sharing Rootly's numbers with recipients in advance prevents most of this.
  </Accordion>

  <Accordion title="Recipients reply and nobody sees it" icon="reply">
    Replies go to the from address. If it is unmonitored, either monitor it or choose a source address that routes somewhere a human reads.
  </Accordion>

  <Accordion title="A communication shows as partially sent" icon="circle-half-stroke">
    Some recipients failed while others succeeded — usually a bad address or unreachable number rather than a problem with the message. Investigate the affected recipients rather than resending to the whole group, which would deliver twice to everyone who already received it.
  </Accordion>
</AccordionGroup>

***

## Related Resources

<CardGroup cols={2}>
  <Card title="Recipient Groups" icon="users" href="/communications/recipient-groups">
    Who receives communications, and on which channel.
  </Card>

  <Card title="Sending a Communication" icon="paper-plane" href="/communications/sending-communications">
    The flow these sources deliver.
  </Card>
</CardGroup>