Audio echo issue in OBS

[pvpd]

Hi.
I stream daily discourse live on YouTube using OBS. Today I have faced a weird problem. The audio echoes after few seconds in the live stream. Here are few more details:

• Under mic "Advanced Audio Properties", I have set "Audio monitoring" to Monitor and Output
• But I am listening to this audio output with a headphone and not any external speaker.
• I am not capturing desktop sound in OBS

Here is the video link. Please listen from 09:40. Please let me know if more details are required.

Thank you.