root@debian-buster-armhf:~# speedtest-cli
Retrieving speedtest.net configuration...
Cannot retrieve speedtest configuration
ERROR: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)>
W takim wypadku sprawdzamy czy mamy i jeśli nie instalujemy ca-certificates
aptitude install ca-certificates