That green/yellow/red indicator is the buffer fullness meter.
Staying red means that OBS is generating data to be sent faster than your network card can send it, so your local buffer is filling up. Think of it like a bucket where the drain is smaller than the water being poured in.
If you haven't already, I'd recommend running R1ch's Twitch Test app, which can help check if your connection to the ingest may not be able to sustain the bitrate you've set, or if there might be a connection quality issue causing re-sends to be forced and eating up that bitrate. You can grab it here:
https://r1ch.net/projects/twitchtest
(edit) Posting a logfile from a session where the issue is occurring would definitely be helpful too, and let us take a peek at anything obvious on the back-end that could be contributing to the issue. (/edit)