If you already knew sorry.
I get regular Amazon emails suggesting pointless questions to ask Alexa so I usually delete the emails without opening. Somehow I saw this and it is marginally useful for anybody that does use theirs. I pretty much only have mine (the screen version) for my doorbell. Anyhow...
We're contacting you regarding your Echo Dot.
A recent software update may have inadvertently turned off an optional feature known as "Follow Up Mode." The feature opens the microphone for a few seconds after Alexa responds to your request, allowing you to ask a follow-up question without having to say the wake word. If you wish to re-enable this feature, just ask Alexa to "Turn on Follow-Up Mode."
For additional information and instructions to turn this mode on via the Alexa App, please see this help page: https://www.amazon.co.uk/gp/help/customer/display.html?nodeId=202201630.
Please accept our sincere apologies for any inconvenience caused by the software update.