I’ve tried this on three different phones. 1 iphone and 2 androids. Currently located in Corpus Christi texas, and driving to Guatemala.
App started complaining that it cannot find endpoint. When opening waze, everything from Mexico south is just blank.
Attached are two screenshots, one from the iphone, the other from an android. 
The US and Mexico/Central America are on different servers. At some point after crossing into Mexico, Waze will switch servers.
If you want to see what’s actually mapped before making the drive, you can switch server environments. Type ##@other into the search bar in Waze then hit the search button. Restart your phone and it should be on the server for Mexico and Central America…and will no longer be able to see anything in the US. Doing the same but changing to ##@usa will switch back.
This doesn’t work. It’s still missing. Followed instruction to the T.
Just tried using a VPN from my phone into Mexico, same story. Doesn’t work. I will be passing the border tomorrow, and be about 8 hours into the country (south) and will update accordingly.
Also, using the web app, you can’t route from the US any longer, through Mexico. This for sure, 100% worked a week ago. And the Mexico map, for sure, 100% showed on my phone, and routed through mexico, about a week ago. So something is up…
Thanks.
VPN has nothing to do with this. It is based on where your phone is physically located. The information I provided above is a way to force Waze to the other server and is no guarantee that it will do what you’re trying to accomplish.
The fact the two countries are on different servers is a long known issue - since before I started editing. We have requested Mexico be put on the same server as the US, but represents a significant technical challenge. I would not expect this change to happen any time soon. Until then, Waze will continue to behave as it does now.
Mike is 100% correct. About the only other thing you can do at this time is to upvote or make a feature request.
The best place to ask for feature requests is here: https://waze.uservoice.com/forums/59223-waze-suggestion-box
We recommend adding your suggestion there, or upvoting a similar suggestion to make it more popular to the developers.