FB Messenger camera doesn't focus

[Stefan]

I moved this to #fairphone2help until it is confirmed that this is not a problem with a third party app.

I’m assuming that you have a FP2? Your original post didn’t say anything about your model.

Does the camera work correctly in other apps?

PS.: Facebook is known to cause problems:

Facebook app causing severe problems (December 2016 app update)

Since its last update, the Facebook app causes severe problems like phone freezes, crashes, battery drain, problems with instagram etc. (see here for example) If you lately experience issues like this, just uninstall the app. Probably your problems are solved.