Maps Marker Pro allows you to choose from different geocoding providers which enables you to get the best results according to your needs. For a list of available geocoding providers and instructions on how to activate them, please have a look at https://www.mapsmarker.com/kb/article/geocoding/.
Please be aware that each geocoding provider uses different sources with different update cycles. Nevertheless it can be, that no result is found for an address, which definitely exists though. If this is the case for you, we´d recommend to switch to another geocoding provider to verify if the exact address is found there, e.g. by using the dropdown which shows all active geocoding providers:
If there is still no result found, you can help all OpenStreetMap based geocoding services (all but Google Geocoding) to improve their dataset by submitting the address. For more information on how to help improve address data for OpenStreetMap, please have a look at the following sites: