I have a Yaesu FT1D that supports APRS messaging. I set the callsign in my radio (via SET:12), and I set my APRS callsign as my callsign with SSID -7 via SET:9>23. (See the FT1D manual here or an explanation about APRS SSIDs here.)
I tried sending a message to CQSRVR and ANSRVR to test, but I never got any replies. I have a low-budget digipeater set up in another room using a laptop and another HT, so I checked the screen. The packets were received, gated, and responses were received, and transmitted, but my radio never showed anything under messages.
I installed PocketPacket (iOS App Store) and using SSID -5 for it. I sent a message from my radio to my -5 SSID. It showed up on my iPhone. I replied to that message, addressed to SSID-7, it did not show up on my radio.
A bit frustrated, I sent a message to my callsign without SSID. It showed up on my radio. However, when I replied from my radio, the -7 SSID was appended, and so replies to the -7 SSID wouldn’t show up.
By changing my APRS SSID via SET:9>23 to my callsign only without SSID, I was able to get messaging working as expected.
So, in a nutshell:
Issue: APRS messages are not displayed on the radio when an SSID of non-zero is set via SET menu 9>23.
Steps to reproduce: Set an SSID to your callsign via the above-mentioned settings menu. Transmit an APRS message from another device to your callsign-with-SSID. It is not shown on the radio. Transmit an APRS message from another device to your callsign-without-SSID. It is shown on the radio.
Workaround: Set menu 9>23 to your callsign without SSID.
Expected behavior: When the SSID is set via menu 9>23, messages are shown as addressed to your callsign-with-SSID.
I will be emailing Yaesu regarding this issue and hopefully they can fix it in a firmware update.