Just guessing... but your Internet speed may NOT be fine. Are you actively monitoring latency and throughput for the entire connection to streaming server entire time you are streaming? I'm guessing No
LOTS of things can happen along a typical Internet path, especially if Public Peering routers are involved. Some Internet providers have silently adjusted down upload bandwidth to deal with all the COVID-19 driven stay-at-home video conferencing activity. So even if you run a speedtest with your provider... that doesn't mean that speed is assured nor consistent all the way to your streaming server. congestion can happen at anytime, anywhere along the path... one fix, if issue is within your provider's loop, is to get business class service with SLAs (vs consumer Internet circuit which is only best effort).. but that won't help once traffic leaves your provider. Then, it may be your streaming host that is being overloaded? Are you using a free or paid hosting service? The fact that you had consistent performance before is no guarantee of future performance... especially when you are using free services
So... most likely there IS a reason.. you just aren't noticing it as it may not be local to your PC but rather between your PC and the server (or the server itself) you are sending your stream to.
Then again... it could be your PC.. My PC for some reason just recently dropped its eSATA throughput to a backup drive to 1/5 normal performance... otherwise everything else appears normal/fine... did a patch, security s/w update, or ?? change something??... phase of the moon ;^) the joys of computers.....
