are you using openHABian as basis? if not, you’re highly encouraged to use it - especially as a new user!
if yes, it should ootb set the permissions already; if they’re not, you could also use the options behind option 10 “Apply Improvements” in sudo openhabian-config, which grant the permissions.
If you’re a bit more experienced in Linux-systems, use the information documented here:
openHABian builds around raspbian OS, so you’re free to use it as basis for OH3 (highly recommended as you also get better support here!) and run your services on the pi in parallel - but in terms of stability and performance I think, it’s not really recommended to run more than necessary on the same pi.
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