Why did Alexa stop controlling my Echo speaker’s aux input — and what’s the fix?

Amazon removed Alexa control of Echo AUX input, so use the cable and speaker controls directly, switch to Bluetooth, or rebuild routines around supported actions.

Amazon removed Alexa’s ability to control an Echo speaker’s AUX input, so a routine or voice command that used to select that input may now fail even though the cable and speaker still work. First reseat the 3.5 mm cable and select AUX with the speaker’s own button or app. If you need voice-friendly playback, pair the source over Bluetooth and cast audio instead.

For routines, replace the unsupported input-switch action with a supported trigger such as starting Bluetooth playback or powering a connected device. Do not factory-reset repeatedly: this is a service change, not usually a broken Echo. Before buying an adapter, confirm which device needs to send audio and which needs to receive it.