If you are hearing feedback or echoes in your meeting, that means there is a device in the meeting that is channeling your audio back.
If you join from a computer and call in from the telephone, please make sure you either:
If another participant is too close to you, and both of you have speakers on, either hang up one of the telephone connections or select Leave audio conference on one of the computers.
If you are in a conference room with multiple devices, disconnect your computer audio from the other devices. Muting your speaker is not enough.
More information and detailed troubleshooting steps for audio echo issues in Zoom are available in the Zoom Help Center.