---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/53403#article
headline: "53403: Server is unable to apply a remote media description"
url: https://www.twilio.com/docs/api/errors/53403
inLanguage: en
dateModified: 2026-06-08T11:29:20.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 53403: Server is unable to apply a remote media description

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when the Twilio Video Media Server receives a remote media description from a participant and cannot apply it. Start by checking client compatibility, because Twilio recommends using the latest Video SDK, supported browser environments, and codec settings that align with the codecs supported by the Video SFU.

### Possible causes

* Your application is using an older Twilio Video SDK release. Twilio recommends updating to the latest JavaScript SDK release.
* If you use the JavaScript SDK, the participant is joining from an unsupported browser or unsupported `WebView` environment. Twilio supports recent versions of Chrome, Edge, Safari, Firefox, and Samsung Internet. iOS `WebView` support requires iOS 14.3 or later and JavaScript SDK 2.21.0 or later. Android `WebView` is not supported.
* Your application is forcing codec preferences that do not match Twilio Video codec support. In Group Rooms, the Video SFU supports `VP8` and `H.264` for video and `Opus` and `PCMU` for audio.
* Participants in the same Group Room negotiated codecs that are not interoperable for a later-joining client. For example, if participants are already sending `VP8`, a legacy Safari browser that can only receive `H.264` may not be able to receive video.

### Possible solutions

* Update all clients to the latest Twilio Video SDK release before testing again.
* If you use the JavaScript SDK, verify that the participant is using a supported browser and check `isSupported` before connecting to the Room.
* Review any codec preferences you set in `ConnectOptions`. For two-participant Rooms, do not force a preferred video codec unless you need to. For Rooms with three or more participants, prefer `VP8` and enable `Adaptive Simulcast`. Keep `Opus` as your audio codec unless you have a specific reason to change it.
* If you prefer `H.264` on mobile clients, confirm that the device supports `H.264` encode and decode before you force that codec.
* Run Twilio Video diagnostics before participants join a Room. The Video Diagnostics Application, RTC Diagnostics SDK, and Preflight API help you test device setup, connectivity with the Twilio Cloud, and media connectivity issues.

#### Additional resources

* [Managing codecs](/docs/video/managing-codecs)
* [JavaScript Platform Overview](/docs/video/javascript)
* [Insights, Troubleshooting, and Diagnostics](/docs/video/troubleshooting)