There are a few things you can try: Sometimes our emails get filtered to a spam/junk folder, so please check there and see if the code email is being sent there.
Also, if you have an Inbox which is full, then our email cannot get delivered. Finally, it could be that our email address is blacklisted by your server for some reason.
If you have an IT department, you can ask a systems administrator to whitelist our domain and IP address. These are the things which need to be whitelisted:
The domains to whitelist are "zinc-app.com" and "email.zinc-app.com"
You also need to whitelist our IP that's been blacklisted: zinc-app.com and 220.127.116.11