Run a test on location ahead of the event and watch the live stream. If it's not playing smoothly it may be that your OBS video settings are too high for the internet bandwidth.
Make sure you test with your actual camera(s) feed, not blank screen or slideshow.
Find out your Upload Speed by visiting fast.com or speedtest.net

Configure your OBS Studio Optimal Settings

Open settings in OBS Studio

Output Tab

OBS Output Tab settings

Choose Output Mode Advanced.

Bitrate: 2000-3000 Kpbs or more. Make sure it's below your Upload speed.
Keyframe Interval: 2

If your computer is struggling to keep up with video encoding use these settings:
CPU Usage Preset: veryfast or superfast
Tune: zerolatency

Video Tab

OBS Video Tab Settings for EventLive

Output Scaled Resolution: 1280x720
Common FPS Values: 30 FPS

Advanced Tab

Make sure you set Automatically Reconnect is enabled, Retry Delay is set to to 1s and Maximum Attempts to a high value like 1000.

Checking status bar

Keep an eye on the status bar while streaming to ensure encoding and streaming are correctly configured.

Check our OBS Troubleshooting guide

Healthy OBS Studio Status Bar (located in the bottom part of the window)

Encoding overloaded error: reduce your resolution, choose faster preset (superfast) and Tune: zerolatency

Dropped frames indicator and insufficient encoding speed (FPS below 30).