Despite using the supplied charger and lead my Tab S3 will not fast charge. The option in advanced settings to fast charge is switched on but always comes up with "Slow charging. For faster charging use the charger that came with your device". It is connected properly but always comes up with slow charging.
I have tried two other Samsung chargers (same type) plus another Samsung phone charger and an Apple charger. I suspect the lead, but I haven't developed another USB C type lead yet.
Thanks for the suggestion though.