I’ve just published version 2.53, which includes an option on the MapPress setting screen to select the geocoder you’d like to use.
Algolia is built on OpenStreetMap data, but it turns out it doesn’t do street number geocoding, even if it’s available on OSM. In other words, it will just show the middle of the nearest street, even if OSM has more specific data. That’s why the address “383 Woodbury Ave, Portsmouth, NH 03801” works on OSM but not in Algolia.
OSM itself seems to have spotty street-level data. It worked for some areas I tried, but not others. You can use the OSM geocoder called Nominatim by selecting it on the settings screen.
I’ve also added a MapBox option. Their geocoder seems to be more accurate.
I tried many other geocoders, but most are based on OSM, and thus are no better than Nominatim. There is one called geocod.io, which looks useful. They are free and seem to be accurate, but only cover the USA.
I didn’t implement geocod.io yet because I wasn’t sure anyone needs it. But if you, or anyone else, would like to have geocod.io (or any other geocoder), added to MapPress, please let me know.