@ramsee Thank you very much for the detailed info and video. May I know when did you purchase the Archer A7? Does this issue occur when you purchased it, or does it happen recently? If it is the...

@Ganganz The adapter can only connect to one network at a time.

@Mik21 Can I have the screenshot of the C80 Status page, does it display a WAN is disconnected? Do you mean the internet will work on the C80 if you change it into access point mode, and plug the ZTE...

@aaron91795 Thanks for replying. Can you please confirm again how often does this issue happen? Does it happen on a specific time period, such as when there is a high loading or traffic? How many...

@ramsee May I know the network layout as well, how is the A7 connected to your network? Is it working as the main router? If possible, we hope you help take a short video about the issue when you run...

@Nurulaien Check this guide: https://www.tp-link.com/support/faq/1538/.