Audio feedback or echo while on speakerphone can be caused by several factors, such as microphone sensitivity, speaker volume, room acoustics, and proximity to the microphone and speaker. Here are some tips to help reduce audio feedback while on speakerphone:

1. Reduce the speaker volume: Lowering the speaker volume can help reduce the amount of sound that is being picked up by the microphone.
2. Move away from the microphone: If you are too close to the microphone, your voice may create feedback. Moving away from the microphone can help reduce this.
3. Use a headset: Using a headset can help reduce audio feedback by keeping the microphone and speaker separate from each other.
4. Improve the room acoustics: If the room you are in has hard surfaces, such as glass or tile, this can cause audio feedback. Adding soft materials, such as carpets, curtains or cushions, can help absorb sound and reduce feedback.
5. Disable noise cancellation: Some phones have a noise cancellation feature that can cause audio feedback. Try disabling this feature and see if it helps reduce feedback.
6. Reboot Your Device: Sometimes, issues with the device's software or settings can cause audio feedback. Rebooting the device can help clear any software glitches and restore the device to its default settings.

By trying these tips, you can help reduce audio feedback while on speakerphone and improve the quality of your audio calls.