@DecoMatters 

Usually this means "Poor network". You could try the following and check if there's any difference:

Don't forget to click on the Save buttom - bootom right on this page.

  @DecoMatters 

Here's a similar case - an exclamation mark in AP mode with a static IP address on the device.

In this case (AP mode - Case1) the connection between devices should be: main router (LAN port) => AX73 (WAN port).

If that's the way you've connected the devices try using a DHCP address reservation on your main router instead of a static IP address on AX73.

Check if there's any difference after these changes.

If the issue still persists change the cable between the main router an AX73 with another one (CAT 5E/6).

You should check the Internet status on every change you made to be able to determine what change may have fixed this issue.