I have email address list as below:

```
email_list = [a@gmail.com, b@gmail.com, c@gmail.com]

```

I converted with below:

```
email_string = ''.join(str(e) for e in email_list)

```

But I got emails are `a@gmail.com b@gmail.com c@gmail.com` which can not be received email, I would like to receive email successfully(Exchange mail server).

my function is as below, I use `Mailbox` of `exchangelib`:

```
to_recipients=[Mailbox(email_address=' '.join(str(e) for e in list(test.user.all().values_list('email', flat=True))))]

```