[SalesForce] Unable to send emails from sandbox

When you create/refresh sandbox, Email Deliverability default to System Email Only. System Email Only allows us to send emails to users or reset passwords.You can run below class, when you create/refresh sandbox.

When you run below class then it will update all System Admin's user's email address and that will eventually send email to user.

global class SandboxPostRefresh_AC implements SandboxPostCopy { 

    global void runApexClass(SandboxContext context) { 

        System.debug(context.organizationId()); 

        System.debug(context.sandboxId()); 

        System.debug(context.sandboxName()); 

        run(); 

    } 

   global static void run() { 

   //List of all emails from the User object  

    List<User> userEmailList = [select Email from User where profile.name = ‘System Administrator’]; 

    for(User uc : userEmailList) 

    { 

        uc.Email = uc.Email.replace('=','@'); 

        //to remove appended domain 

        String addedPhrase = '@example.com'; 

        uc.Email = uc.Email.remove(addedPhrase); 

        userEmailList.add(uc); 

    } 

    if(userEmailList.size() > 0) 

    { 

         Update userEmailList; 

    } 

    } 
} 

After wasting 2 days on this issue, I submitted a case with Salesforce Support and debugged it with the Support, affected user and myself.

What we noticed was NO emails was being sent for when we used the test user not coming to both our company or personal email inboxes.

It was found that the user that is triggering the Email Alert has the email suffixed with the '.invalid' which won't trigger any email and won't appear in the Email logs.

So when testing Email alerts on sandbox, REMEMBER to use a test user with a valid email format (without the .invalid that is automatically added when refreshing sandboxes)