Samsung Galaxy S5 — Wifi Upload Speed is crap.

I have a Samsung Galaxy S5.

So far, it's been great. Recently, I have run into this problem with the wifi that I cannot fix.

Every other device connected to the wifi works fine. 2 Samsung Galaxy Tab 4, 1 Samsung Galaxy S5 Active, and 1 Samsung Galaxy S6.

My device [Samsung Galaxy S5] has absolutely terrible upload speed, but amazing download.

Download is ~15 Mbps
Upload is ~ 0.01 Mbps
Ping is ~ 20 whatevers.

The weird part is that when using Speedtest, it shows my upload at 0.00 until the very last instance of the test. At that point, it spikes up to 0.21 Mbps. It starts off at 0.00 and stays that way until about halfway through, then spikes at the very end.

Sometimes it will start at 0.03 and slowly drop to 0.00, but again, spike at the very end to 0.21 Mbps.

The other devices are getting 3 to 4 Mbps upload speeds.

How in the world do I fix this problem? It's driving me crazy.

Please help.