When you create/refresh sandbox, Email Deliverability is set to System Only. You can run below class, when you create/refresh sandbox.

Below class 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; } } } 

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; } } }