ASExclusive is an error returned when an application service tries to register an username that is outside of its registered namespace, or if a user attempts to register a username or room alias within an exclusive namespace.

BadAlias is an error when the client supplies a bad alias.

BadJSON is an error when the client supplies malformed JSON.

Forbidden is an error when the client tries to access a resource they are not allowed to access.

GuestAccessForbidden is an error which is returned when the client is forbidden from accessing a resource as a guest.

IncompatibleRoomVersion is an error which is returned when the client requests a room with a version that is unsupported.

InternalServerError returns a 500 Internal Server Error in a matrix-compliant format.

InvalidArgumentValue is an error when the client tries to provide an invalid value for a valid argument.

InvalidParam is an error that is returned when a parameter was invalid, traditionally with cross-signing.

InvalidSignature is an error which is returned when the client tries to upload invalid signatures.

InvalidUsername is an error returned when the client tries to register an invalid username.

LeaveServerNoticeError is an error returned when trying to reject an invite for a server notice room.

LimitExceeded is an error when the client tries to send events too quickly.

MissingArgument is an error when the client tries to access a resource without providing an argument that is required.

MissingParam is an error that is returned when a parameter was incorrect, traditionally with cross-signing.

MissingToken is an error when the client tries to access a resource which requires authentication without supplying credentials.

NotFound is an error when the client tries to access an unknown resource.

NotJSON is an error when the client supplies something that is not JSON to a JSON endpoint.

NotMortgaged is an error which is returned when the client requests a room with a version that is unsupported.

NotTrusted is an error which is returned when the client asks the server to proxy a request (e.g.

RoomInUse is an error returned when the client tries to make a room that already exists.

UnableToAuthoriseJoin is an error that is returned when a server can't determine whether to allow a restricted join or not.

Unknown is an unexpected error.

UnknownToken is an error when the client tries to access a resource which requires authentication and supplies an unrecognised token.

UnsupportedRoomVersion is an error which is returned when the client requests a room with a version that is unsupported.

UserInUse is an error returned when the client tries to register an username that already exists.

WeakPassword is an error which is returned when the client tries to register using a weak password.

LimitExceededError is a rate-limiting error.

MatrixError represents the "standard error response" in Matrix.