@Marc1 just check this site it might help you identify the issue
Thanks for your reply.
I already troubleshoot with this site.
The MX84 from location A is connected to a D-Link 4G router, which runs DHCP. Is it possible that a rule needs to be created on the D-Link?
so you have a non meraki device on the topology right?
The D-Link Router is my Gateway to the Internet.
Do you know if I need to make any specific settings on the ISP router? Or do you have another idea what could be?
Can you give the MX a reboot?
I already reboot the whole Network.
@Marc1 if then you have considered all the necessary steps for troubleshooting then i suggest you contact meraki support or @MerakiDave who is here can assist