Hello  @vanQ 

When the error occurs, confirm phone has good internet status, connect to home wifi network, or using mobile data .

Turn off VPNon the phone if there is any. 

If ' Alexa' failed to authorize the tp-link account, here are some tips to give it try: 

What should I do if I cannot make Tapo smart devices (smart plug, smart camera, smart lighting) work with Alexa or Google Home

You could also try a different phone to authorize the account. 

Try to enableTapo Skill from Amazon web page  https://alexa.amazon.com

If the concern persists despite the above step, can I have a photo of error message, your TP-Link ID ( please share via private message) 

  Hello @vanQ 

Try to enableTapo Skill from Amazon web page  https://alexa.amazon.com

Try a different mobile device if you have , ensure that device has internet

Confirm Tapo APP is up to date

If possible, can I have take a video of the issue and share the video link here, can I know 1) Tapo APP/ Alexa APP version. 

2) Model of phone and its Andriod or IOS version 3) please share MAC address of your tapo device by private message. Thank you.