Cannot download Graphhopper maps

I am new to all this, but want to be able to create a route following mountain paths offline. I have downloaded Brouter OK and map segments OK, and this will work for roads and tracks, but does not have enough data it seems to follow mountain paths.

Online, Graphhopper works very well on moutain paths, but I cannot get the maps available in https://graphhopper.develar.org/ For offlline use..If I try to download the map as a zip file on the PC, firstly I get loads of warnings it is an unsafe site, and if I ignore these warnings, the zip file is not available on the server. If i try to download it using the browser window on the phone and using the Locus button, then a Certification failure notification. I have Chrome with Javascript enabled on the phone.

I cannot seem to make any progress, any help much appreciated

ian