There is a setting in the app to change the port (don’t change it in the Web GUI!). You need to set it to 0.0.0.0:8384 for remote access. Please also be aware that on Android, the username is hard-coded to “syncthing” and the password to the API key, and you cannot change them for now. //

(App menu > Settings > Syncthing Options > GUI Listen Addresses > 0.0.0.0:8384)

(App menu > Web GUI > Settings > GUI Tab > GUI Authentication User).

Just for the record, if you do change them in the Web GUI, they will reset back to “syncthing” and the API key after restart. This is a known issue and limitation.