he next option to validate is that your ISP allows communication from the MX to the Meraki Cloud platform
If the ISP confirms that it does not block ports, it tries to connect Port 2 of the MX84, to isolate a possible defect in the physical interface 1.
If these options do not work, assign a fixed IP of the segment provided by your ISP on WAN 1 or WAN 2, whichever you prefer.
Regards.