Hello Jagadeesh,
Please check in your mendix user lib folder there is no duplicate jar file ,if so remove all.
Check below for further steps.
Mendix Community - Exchange Details
Mendix Community - Question Details
i have created video on how to implement email connector on mendix
@RajuPatel-r6q in youtube
Please check if that will help.
See the forum post here: https://community.mendix.com/link/space/app-development/questions/141643
Regards
Ronald