So this has been bugging me for a couple weeks now. My position beacons are showing up fine on aprs.fi, people can see me moving around when I'm mobile, all that works great. But whenever I try to send an APRS message to another station — like an actual text message through the network — it just disappears. The other guy never gets it, and I never get an ack back.

I'm running a TM-D710G with the built in TNC, connected to a mag mount on the truck. The RF path shows WIDE1-1,WIDE2-1 and I can see my packets getting digi'd and hitting the IS through a local igate. So the path is definitely working for position reports. But messages just vanish. I've tried sending to a couple different guys who are definitely on the air and active, checked their beacons on the map, they're right there. Nothing goes through.

Is there something specific I need to configure differently for messaging vs just beaconing? I feel like I'm missing something obvious but I cant figure out what it is.

This is actually a pretty common gotcha with the D710. The thing to check is whether the stations you're trying to message are RF-only or if they're also connected to the APRS-IS somehow. APRS messages on RF work fine between two stations that are both on RF in the same coverage area, but if the other guy is, say, running an Kenwood HT with a low power setup and his packets are only barely making it to an igate that's receive-only, then your message might be hitting the IS just fine but there's no two-way igate in his area to push it back out to RF where he can hear it.

Also check your message retry settings on the radio. The D710 will retransmit unacked messages but I think by default it only tries a few times before giving up. If the path is even slightly congested you might just be losing packets. Try reducing to WIDE1-1 only and see if anything changes — sometimes the extra hop actually hurts more than it helps depending on your local digi layout.

yeah i had same issue a while back, turned out the igate near me was rx only and never gating anything back to RF so messages from the IS side were just dying. found a site that lists igate capabilities, cant remember the name but you can check if your local igate is bidirectional or not. if it aint bidirectional then messages are basically one way and youll never get acks from stations that arent in your RF footprint directly.