Hi,
Are the normal emails of HikaShop being sent properly ? And received by the recipient ?
Normally, when you click on the "resend" button for an email, a new entry for that email will be added to the Customers>Email history list for that new email. So if you see it there, it means that HikaShop sent the email to the email server of your hosting. If the email is not received, it's likely that it was rejected at some point, either by the recipient email server (most likely) or your email server (less likely) because it was flagged as spam, or the mailbox is full, or the email address is wrong or something similar.