Why Won't My Speaker Stay Connected?

I've had my JBL Flip 3 speaker for just under 2 years and it recently started disconnecting itself from my phone and turning itself off. The speaker is fully charged so it isn't the battery. After a minute or less after connecting the speaker to my device it will light up, aka the power button + the connection button + the battery life indicators. However the fifth battery indicator light turns red. Does anyone know what this means or has anyone else experienced this before?

I have no reason to believe it's the phone I'm connecting it to either.