Outdoor Active Map Sources are not available for free like some other sources are.
They were removed in version 4.5.6 of BackCountry Navigator.
OutdoorActive is willing to license them, along with their POI and track data, for a small fee. We are collecting feedback from those who are interested to see if there are enough.
Take this survey:
Alternatives to them include:
- 4umaps.eu - Free Topographic Map of Europe
- Germany Digital Landscape Server
- hikebikemap.de - Not yet in BackCountry Navigator, but will be.