Stream is lagging on Twitch?

Recently my stream in OBS has been lagging a lot. I have a very constant frame rate of the usual 60 FPS and a constant bit rate of 5000. In addition, it only lags on Twitch, so not in OBS. This phenomenon only occurred 2 streams ago.
My system:
CPU: Ryzen 5 2600x

GPU: RX 5700

RAM: 2x8 GB Corsair Venegance RGB PRO @ 3000MHZ

MoBo: ASRock B450M Steel Legend

And as far as the utilization of the CPU is concerned, it was always 30% in the stream, graphics card at 70% -80%.

Jo, I would say that is due to your connection to stream 1080p to 60 fps, that needs a thick line. Maybe there's something on the download that is overloading the line

First of all thanks for your answer. In fact, it downloaded something in the stream, then canceled it, and didn't get any better. But currently I'm streaming in 1600x900 with a 100 line and 50 upload.