What can I do if I am experiencing an echo during my lesson?

Please try the following: 

restart the device, use headphones during the lesson, check to make sure there are no other audio devices connected and run a pre-call test.

 

 Pretest call: https://tokbox.com/developer/tools/precall_doc/

 Check Audio Setup:

https://www.support.limlessons.com/hc/en-us/articles/360043139314-Problems-with-Camera-Microphone-Access