Why does the Shanren Sport Navigation service show 'offline'?

I have a Shanren Discovery Pro bike computer paired to my Google Pixel 6a. I use the Shanren Sport app from Google Play Store. The Shanren app has a navigation service which displays directions on the bike computer. However any attempt to use this displays a message such as or a toast saying 'offline'. However all other aspects of the app work fine, including displaying my rides on a map (which appears to be Google Maps). I assume that the app is using some third party navigation service which it cannot reach from my country, or which is out of service. All permissions are granted. Further diagnosis shows an attempt to connect to https://api.mapbox.com App: Shanren Sport (10370) Protocol: HTTPS (TCP) SNI: api.mapbox.com Source: 10.215.173.1:48856 Destination: 18.239.236.44:443 Status: Closed Country: United Kingdom ASN: AS16509 - Amazon.com, Inc. Traffic: 1.4 KB received — 1.2 KB sent Packets: 8 received — 7 sent Payload: 2.0 KB Duration: > 1 m First seen: 07/24/24 11:20:49.589 Last seen: 07/24/24 11:21:51.371