After having also problems while charging my FP1 (2 years old), but not see a loosen connector, I tried to clean also the connector itself from dust and lint with a very small screw driver.
my charging problem is not gone completely, but become remarkably better!
I was inspired by this video and surprinsingly I really could remove a lot of dust, although at first look it does not seem to be that bad. During cleaing it really looked like this pic in the video…
But be careful not to bend down the inner part of the connector or scratching the contacts!
For cleaning a soft brush (electrical tooth brush?) and/ar a gas duster as stated above should be a fine finish.
Cheers, Robert
Edit1: Cross link to my other connected post: