I am in the process if switching all of my asa's with Meraki mx and was attempting a test at my main location and it doesn't seem to like me. Here is what I have tried as far as settings for the MX84 at my main location.
I have a static IP from the ISP and entered that in the management portion of the device and it will not connect anywhere and I have left the settings alone on the device with exception of assigning the LAN IP. If I let the the device pick up DHCP it get a weird IP but it does connect to Meraki Cloud and does update and all that but will not provide an internet connect to the rest of the devices hooked to the switch. I am new to Meraki and figure this is an easy fix for some of you that are experience.
Depending on your MX version, MX 13.x allows you to assign a static IP address via Uplink tab.
In previous version, you connect via management port or directly and use a web browser to http://mx.meraki.com/
In there, you choose Configure tab, enter username and password as setup in Network General setting (or if you haven't connect to the cloud yet, device serial number and blank password). You can set a static IP address for the Uplink ports afterwards.
I had to plug into management port to make the changes, but when I do and put in Static WAN IP it won't connect to Meraki cloud or give internet. When I switch back to DHCP it will connect to Meraki Cloud but not give internet to rest of network.
Sounds like your static IP addressing is incomplete, make sure you have the correct addressing, subnet mask, gateway and dns.
Secondly, when on DHCP mode, your internal network is not accessing the internet. Make sure your MX is set to NAT mode, and that the connection does not drop traffic that you need, since MX will drop untagged traffic by default.
Did the existing ASA use a static configuration?
When statically configuring the MX are you also assigning DNS servers (which is critical, and the ASA may not have had this before)?
When statically configured, you can look at the local status page and it should say what the problem is. What problem does it report?
Does your ISP require you to register the MAC address with them for the Static address to work ?
Also after setting the static in your MX device - reboot your ISP modem to clear out the old cache etc for the old ASA and have the MX request the static IP from the modem.
Ive had to do both before to get MX working with static IP.