Issue with users receiving emails from Passle?

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Ensuring Passle can send emails to your users


'Allow listing', helps to ensure Passle can send emails to your users


If your company uses Mimecast or similar email security services that try to decide if email content is spam, phishing or similar and blocks it as a result, you might find that emails sent from Passle are not being received. This happens when the email management software decides that because they are coming from an unknown source and should be blocked.

To resolve this issue, your email service can be configured to "allow list" Passle as a permitted sender.

Exactly how you configure the software or service can vary depending on the provider you use, making it difficult to provide general instructions however, this page aims to provide you with the technical information we believe you will need. Your IT team will know what to do with this information, but if there are any additional queries, please do contact us.

Most filters work on "From" or "Sender" addresses, if your internal network blocks your users from receiving email from certain domains, or re-routes emails from those domains to a spam folder, then please ensure the following domains (including all subdomains) are allowed:

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Our SMTP Server (from which outbound emails are sent), IP addresses are,

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If you need any further information, please get in touch via and we will do our best to help make sure you have everything you need to ensure reliable delivery of your emails and access to Passle domains.

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