Understanding SMS Delivery in Otto – Otto

Most text messages Otto sends reach pet parents in seconds. When they don't, it's helpful to know why and what happens next. This article walks through MMS support, what Otto does when SMS delivery fails, and how to read the error messaging in conversations.

MMS — sending images and videos

All Otto clinics on Twilio support MMS (multimedia messaging), which means you can send images, photos of discharge instructions, and short videos directly in a conversation. Pet parents receive them as part of a normal text thread on their phone.

If your clinic is on Bandwidth, MMS support is limited — reach out to Otto Support if you need to send images regularly.

When SMS fails — automatic Pet Portal fallback

For clinics on Bandwidth, if a direct text fails to deliver because the carrier flagged it as spam or filtered it for content, Otto automatically:

Delivers the original message to the pet parent's Pet Portal inbox.
Sends them a short notification SMS pointing them to the Pet Portal to read the message.

This means the pet parent still gets the information — you don't need to do anything. The error message in Otto has been updated to confirm this: instead of "Message Not Delivered," you'll see "Text Not Delivered — Message sent as Chat Notification to Client Instead."

The pet parent still receives all other notification channels they're opted into (email, push). The fallback adds the Pet Portal chat layer for cases where SMS itself was blocked.

Reading SMS error messages

When an SMS fails for a reason that isn't a carrier filter, Otto shows a clarified error explaining why. The most common categories:

Landline / non-mobile number — the number on the client record isn't a mobile line. Update the contact record in your PIMS to a mobile number.
Opted out — the client previously texted STOP. They need to text Start to your clinic number to opt back in.
Invalid or disconnected number — the number isn't in service. Verify contact info in your PIMS.
Blocked by carrier or recipient — the carrier or the recipient's device is rejecting messages.
Temporary failure — a transient issue. These usually retry automatically; if you see a pattern, escalate to Otto Support.

When to escalate

If your overall SMS failure rate (visible in the System Health Dashboard under SMS Failure Rates) stays above 5–8%, that's worth investigating — most often it's caused by landlines being saved as primary contact numbers in the PIMS, but persistent carrier filtering is also something we can escalate to the carrier on your behalf.