Cannot email New POS Invoice

I am unable to email new POS Invoice Receipt after I Complete Order;
When I click on “Email Receipt” it offers me the option to provide the email address.
After I input the email address and I click Send it shows a notification “Email Sent Successfully.” But the email is not sent. When I look at the error logs two new errors are generated as shown below:
one error says “”
and the other is show in the screenshot below

my installation is as follows:
erpnext 13.9.2
frappe 13.9.1

I can send other types of emails from within erpnext meaning my Email Domain (gmail) and Email Setups are working.

Please help, thank you in advance.