As mentioned here:
https://mapwindow.discourse.group/t/openstreetmap-tiles-and-5-0-1-1/180
I tried adding
to the SecureHttpClient constructor, but currently I'm having problem compiling MWGis, so can't check if this is solving the problem.
I've solved the compile errors and see that adding the user-agent is solving this issue.
I will enhance it so users can set their own user-agent.