E-mail anti-spam services are good at filtering out malicious and harmful e-mails, they usually work by acting as the ‘middle man’ between the sender and your mail server. The anti-spam service will scan the incoming mail for any malicious code, offensive text and even by the e-mail server that the sender is using as well as a few other checks.
E-mail servers will use the rules above to decide if an email is legitimate, but sometimes this service isn’t perfect and can raise a red flag for legitimate emails. For example, if a website asks you for email confirmation it will tell you to “check your junk mail” folder – this is because it can be mistaken for spam by the rule-based filter which isn’t uncommon.
There is a useful tool on the internet called MXToolBox. This is a diagnostic website that can show you the properties for domain names and email addresses. You can use MXToolBox to troubleshoot certain problems with your domain / e-mail by using their MXLookup tool; For example, you can use the “Blacklists” tool to see if your company (or another) have been blocked by any email blacklists which is very useful if your recipients say they aren’t receiving your emails. Being on an e-mail blacklist would mean that most if not all your e-mails will be blocked from being received as you’re a ‘known spammer’.
To see if you have any emails being held up in your spam filter, you’ll need to go through your spam management provider’s website and login to see if they have quarantined any emails you have been expecting. – Make sure to be careful when browsing through your quarantined emails though, they have all been blocked because of red flags that could potentially contain malware so only release e-mails that are from known sources.
If you’ve checked your spam filter and still can’t see an e-mail then it’d be best to speak to your IT team as usually they’d be able to check in more detail on the server itself and can provide you with a definitive answer.