Thanks again to everyone who chimed in on my traffic problems!

Turns out that that problem was sooo trivial that I'm almost too embarrassed to share:

I had this line in my sys.txt: profile="nng-igo-tmc-jci"
And it should have been this: profile_name="nng-igo-tmc-jci" Doh!

After changing it thus, traffic infos started to download as they should