See FAQ on this site
https://obsproject.com/kb/stream-connection-troubleshooting
Realize, the issue could be
- your PC (nothing to do with OBS Studio)
- Your OBS Studio settings relative your your PC's capabilities and/or your stream destination's requirements
- other traffic (or security settings on firewall/??) on your LAN contending for (or restricting) upload bandwidth
- Your WAN connection, your ISP provider, and its traffic routing
in my last 4 years here, that list is in descending order of likelihood
Also, don't ignore pinned post in this forum (link in my .sig) regarding posting your OBS Studio log when having an issue/asking for help
