[CE 2.1 bug] Braintree payment method - error printed in sent order email

[kishanpatadia]

I upgraded to Magento 2.1 CE from Magento 2.0.7 and tested order process. Order email is working in chque/money order and other payment method. But when I pay using Braintree credit card, order email is received but it has following content in email.

"We're sorry, an error has occurred while generating this email."

I tried many solution but unable to resolve it. Can you please help solving it ?

[andimov]

@kishanpatadia
To allow us to research the issue, please, format description according to the Issue reporting guidelines: with steps to reproduce, actual result and expected result.

[andimov]

According to contributor guide, tickets without response for two weeks should be closed.
Please feel free to reopen if it's needed.

[kishanpatadia]

Using Magento 2 and Braintree Payments. When payment is by credit card email copy of invoice fails to generate as per attached picture.

Steps to reproduce:
Navigate to store front-end
Add any product to cart
Go to checkout page
Select braintreee credit card payment method
Place order by completing other steps

Expected result:
Order invoice mail is generated successfully and customer receives it in email.

Actual result:
Invoice order email is failed to generate and customer gets that error message in email