this is not an error and you can just turn off the message if it bothers you, see:
your runtime issue is also not related to this, your snap seems to not ship libblas or you are missing the necessary LD_LIBRARY_PATH entry to find it in the /atlas subdir of your library path … just add the necessary bits to your apps: environment: block and you should be good …
here is an example where i use libblas: