Fitbit replacement will not charge or reset

[danig8]

My <1 month old Sense failed (stuck on the Fitbit blue diamond screen) back in January.  The replacement showed up today, 34 days later.  I put it on the charger and it started charging right away.  Then I went to my phone and connected to it.  It said it needed to do a firmware update to 128.6.12.   That took maybe 10-15 minutes.  As soon as it was done, it would not charge anymore.   No combination of outlets or USB ports works.  The connections are clean (and they worked fine when I first plugged it in).   Holding the side button for 10+ seconds does not trigger a reset.  My phone can connect to it, though.  So now what?

[danig8]

Since then, I have tried a factory reset, restarting the app, forgetting and repairing the Sense, turning it off through the app, and connecting and reconnecting to the charger several times with no change.  It has not charged since the firmware update.

Edited to add:  I wonder if it's the charging cable.  Even with the first Sense that I had, it always said "slow charging" regardless of where it was plugged in (through a USB port, through a wall outlet, etc)

Edited yet again:  It's the charger.   It's really really finicky, but it is charging (slowly) now.  Better than not at all.

[eezeepee]

I pretty much get the "Slow charging" notification every time but more than 9 times out of 10 ot actually still fast charges just fine. If I have any Issues with getting it to even charge or it actually does slow charge, I just take it off the charger and put back on and/or wipe the contact points.