django-ses | A Django email backend for Amazon 's Simple Email Service | Email library

Try avoiding the .env file to rule that out.

Update settings.py

The keys to be provided to send Emails are not "SMTP Credentials" . The keys are instead Global access key, Secret access key pair which can be retrieved.

https://docs.aws.amazon.com/ses/latest/DeveloperGuide/send-email-concepts-credentials.html

according to Your questions i think that firstly, when sending mass mail, You should take into account the reputation of Your SES account which can drop down massively if You decide to buy a recipients email list. In order to achive that, it is good to use Dedicated IP's in SES. Here is link to that: https://docs.aws.amazon.com/ses/latest/DeveloperGuide/dedicated-ip.html

According to Your questions:

1. The best way would be to include them in bcc header, as You have set, the limit can depends on SMTP server. According to the AWS, it is 50 recipient's per message. So what You can do is You can group all of the mails and make one call with 50 recipients so it would lower Your request amount significantly.

2. Mass mailing has two approaches. One that, You have already tried(so one by one, and the other one which is considered better -> sending in bulks, as described above). If You would like to check something about for instance bulk sending You can see it there: https://aws.amazon.com/blogs/messaging-and-targeting/introducing-email-templates-and-bulk-sending/ Also, it is good to use only BCC field. You are ensuring Yourself, that there will not be any mistakes in displaying to the recipients email addresses of the other users.

3. Check that links, that I have already provided.

4. Yes, it is. You can easily use amazon ses templates, or create Your own ones. Also, the customization, managing Your own domains, configuration sets is really helpful and the documentation is quite good. However there are small drawbacks, and some minor bugs(for instance when You verify the domain, and it doesn't work instantly, there is a possibility that removing and adding it one more time fixes it :) ) However You have to be careful about Your reputation on SES.

5. Practises:

• Don't use TO/CC, instead use BCC
• Always monitor Your sending reputation, unless You want Your account to be blocked
• Invest in dedicated ips
• Block emails, which had already bounced before(Amazon has it's own suppression list, however it is much better to have one more on Your side)
• Be aware of the sending quota, that You already have assigned and extend it for Your purposes
• Don't buy email list
• You can verify recipient's emails address existence before email sending
• Be aware of the compliaints
• Don't use link shorteners

This was caused by a blank password supplied in config resulting in an un-usable password being set. User.objects.create_superuser sets an unusable password when an empty string is supplied. The docs say:

If no password is provided, set_unusable_password() will be called.

https://docs.djangoproject.com/en/3.0/ref/contrib/auth/#django.contrib.auth.models.UserManager.create_user

However an empty string seems to be treated as "no password" (which was unexpected, although not so surprising given Python's falsy treatment of empty strings). There was a bug in the configuration of the service which caused an empty password to be passed to it.

The reason for the unexpected different format is that an un-usable password appears not to use the same hash function structure.

By looking at the log file, I have identified it was issue with requirement.txt pycurl. It was not getting installed properly.