Send Email workflow not working

Hi,

I am trying to have an email sent to the customer service manager everytime a field in the account entity changes, example "Customer Rating"

However the email is not coming through. We are using CRM Online.

Wondering if I am doing something wrong in setting up the properties of the workflow. 

So I have put in a check condition that if the field "Customer Rating" equals "Weak" send email .

And then clicked on the "Set properties" .

for From I have selected my name from users and in the To section selected the managers name from users list.

Can somebody please advise what am I doing wrong? Thanks heaps