Hello.

I'm trying to understand what happened with daily email limit on Developer Edition. About a year ago our team worked on the specific feature which generates hundreds of emails and sends them to internal SF users using SingleEmailMessage and its setTargetObjectId method. I remember that everything worked perfectly on Developer Edition, Sandbox and PRD (we even were able to send some thousands of emails without any problems and limits).

As of now, we're working on another feature which should generate and send many emails too. But we found that SF can't send hundreds of emails now on our Developer Edition.

I've tried to analyze the problem, but didn't find the reason:
- there are no any exceptions in logs;
- when I look at a log it says: "EMAIL_QUEUE" (email is queued);
- I even tried to reserve email capacity using the code like this Messaging.reserveSingleEmailCapacity(numberOfEmails);, but didn't get any exceptions (limit is still free).
Everything works correctly, but emails are not sent to SF users.

So, my questions:
1) is there a specific limit for emails on Developer Edition? If it's true, then what is the daily limit?
2) did I miss something in the SF documentation? I considered this description:
If you use SingleEmailMessage to email your organization’s internal users, specifying the user’s ID in setTargetObjectId means the email doesn’t count toward the daily limit. However, specifying internal users’ email addresseses in setToAddresses means the email does count toward the limit.


I'm providing a test code for those who want to check it on his Developer Edition:

//1) generate and send emails
List<Messaging.SingleEmailMessage> messages = new List<Messaging.SingleEmailMessage>();
final Integer NUMBER_OF_EMAILS = 300;
for (Integer index = 0; index < NUMBER_OF_EMAILS; index++)
{
    Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
    email.setTargetObjectId(UserInfo.getUserId());
    email.setSubject('Test : ' + index);
    email.setPlainTextBody('test');
    email.saveAsActivity = false;
    messages.add(email);
}
Messaging.SendEmailResult[] results = Messaging.sendEmail(messages, false);

//2) print the results
for (Messaging.SendEmailResult result : results)
{
    System.debug(result);
}