My FP2: 4 years and counting

That’s inconvenient, but this luckily sounds like software would be the culprit, not hardware.
A factory reset should help with that …

https://support.fairphone.com/hc/en-us/articles/115001610926-How-to-make-a-Factory-reset-on-Fairphone-2-

And if this doesn’t help, you can even get more serious …

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