This topic provides answers to some commonly asked questions about calling the API operations of ApsaraMQ for MQTT.

Why does the timeout error occur on an irregular basis when I call API operations?

ApsaraMQ for MQTT limits the frequency at which an API operation can be called. The frequency is measured by queries per second (QPS). If the maximum value of QPS is exceeded, throttling is triggered. For information about the limit rules and values, see QPS limits.

Why is the SignatureDoesNotMatch error returned after I call API operations by using the SDK mode?

The authentication failed. Check whether your AccessKey ID and AccessKey secret are correctly specified. For information about how to obtain the AccessKey ID and AccessKey secret, see Obtain an AccessKey pair.