There are many other posts where exactly the same problem is discussed in none there is an fix for this problem.

I have already contacted you at support@zohomail.com with all the screenshots you require ( plugin screenshot, connected app screenshot and configure account screenshot)

FYI, I have activated and deactivated the plugin several times and even reinstalled it. Client Id and secret have been carefully copy pasted into wordpress. Even erased the profile in the console and generated new id's.

Nothing work. 

Appreciate your help.