如果您正在使用Agora.io进行Web视频通话，并遇到“ declined”错误，则可能存在以下原因：

1. 用户已拒绝视频通话请求。
2. 用户无法接听视频通话（例如，用户正在进行另一项任务）。
3. 某些网络错误或故障。

以下是一个示例Agora.io web视频通话应用程序，该示例显示了如何处理“decline”错误：

var client = AgoraRTC.createClient({mode: 'live', codec: 'vp8'});

// Join a channel
client.init(, function () {
    console.log("AgoraRTC client initialized");
    client.join(, , , function (uid) {
        console.log("User " + uid + " join channel successfully");

        // Create local stream
        var localStream = AgoraRTC.createStream({
            streamID: uid,
            audio: true,
            video: true,
            screen: false
        });

        // Initialize local stream
        localStream.init(function () {
            console.log("getUserMedia successfully");

            // Publish local stream
            client.publish(localStream, function (err) {
                console.log("Publish local stream error: " + err);
            });
        }, function (err) {
            console.log("getUserMedia failed", err);
        });
    }, function (err) {
        console.log("Join channel failed", err);
    });
});

// Event listener for remote stream added
client.on('stream-added', function (evt) {
    var stream = evt.stream;
    console.log("New stream added: " + stream.getId());
    console.log("Subscribe ", stream);
    client.subscribe(stream, function (err) {
        console.log("Subscribe stream failed", err);
    });
});

// Event listener for remote stream removed
client.on('stream-removed', function (evt) {
    var stream = evt.stream;
    console.log("Stream removed: " + stream.getId());
    stream.stop();
});

// Event listener for peer leave channel
client.on('peer-leave', function (evt) {
    var uid = evt.uid;
    console.log("Peer leave channel: " + uid);
});

// Event listener for connection lost
client.on('connection-lost', function (evt) {
    console.log("Connection lost");
});

// Event listener for failure
client.on('failure', function (evt) {
    console.log("Failure");
});

// Event listener for peer online
client.on('peer-online', function (evt) {
    console.log("Peer online");
});

// Event listener for peer offline
client.on('peer-offline', function (evt) {
    console.log("Peer offline");
});

// Event listener