It's probably a crap VPN, do a speedtest with and without the vpn on to see the difference. I don't use a VPN personally.i have one but don't use it for IPTV.

If your IPTV buffers rather than stops, it isn't a blacklist/whitelist issue, it's a bandwidth issue

Either your VPN is slow (likely if you're paying $18 for two years), or your home connection is marginal on speed for the stream, and the extra overhead from the VPN is pushing it from "just about fast enough" to "not quite fast enough"

I suspect the former

It will never work the way you're doing it. A fire stick absolutely is NOT POWERFUL enough to encrypt AES(128/256) packets at that rate AND stream AND decode the video. I imagine the CPU is maxed out. See if they support the cypher "blowfish, or twofish" - those encrypt much faster on most CPU models.

You should be looking at running it on your router, as that will offload all the work from the fire stick. Even my semi powerful s905 devices can't keep up with streaming HD video if I run the VPN locally on that box.

I had a look at their pricing, $9/month and $90/year how did you get 2 years for only $18?

lol i'm the opposite.. probably due to my sucky ISP throttling everything.