We have occasional reports of invoices and purchase orders being auto-approved or rejected when the approval email gets sent out to the users. This then stops the user from clicking the link as its already been done and therefore the link has expired. In order to fix this please find the relevant information below for specific software causing the issue. This is caused by software running on the users PC. 

First please ensure that the following domains are allowed to bypass the spam filter by marking them as safe senders. This should sort almost all issues to begin with. You can do this on MessageLabs, Barracuda, and Office365 so ensure this is done first before following the specific instructions below.

https://myzahara.net

https://zahara.local

Office 365/Outlook Online – For Single users

1. Click on the Gear icon in the top right corner (left from your own profile image).
2. Open the Options page:

• Outlook on the Web (OWA) for Office 365
  
  My app settings-> Mail
• Outlook.com
  
  Options

1. In the Options’ Navigation Pane on the left choose:
   
   Mail-> Layout-> Link preview
2. Uncheck the checkbox in front of: Preview links in email.
3. Press the Save button at the tab.
4. Press the Back button or Options header at the top of the Navigation Pane to return to your Mailbox.

Office 365/Outlook Online – Disable for all users (Admin required)

When you are an Office 365 administrator and want to disable the Link Preview feature for all the users in your tenant, you can do so via the following PowerShell command.

1. Connect to your Office 365 Exchange Online tenant using PowerShell with an administrator account.
2. After logging on, execute the following command;
   
   Set-OrganizationConfig –LinkPreviewEnabled $false

This will completely disable the feature for all your users and they won’t be able to enable it themselves anymore either.

Barracuda

At issue is a part of the Barracuda email filter called the intent filter. There are 3 different modules to this filter.

• Intent analysis – Markers of intent, such as URLs, are extracted and compared against a database maintained by Barracuda Central.
• Real-Time Intent Analysis – For new domain names that may come into use, Real-Time Intent Analysis involves performing DNS lookups against known URL blocklists.
• Multilevel intent analysis – Use of free websites to redirect to known spammer websites is a growing practice used by spammers to hide or obfuscate their identity from mail scanning techniques such as Intent Analysis. Multilevel Intent Analysis involves inspecting the results of Web queries to URLs of well-known free websites for redirections to known spammer sites.

According to Barracuda support it is the multilevel intent analysis module responsible for clicks on links. From the behaviour descriptions we’ve seen from different people, it appears at least some ESP click tracking domains are included in the “redirectors” category.

This will need to be disabled to resolve the issue.

MessageLabs

The Click-time URL Protection service is available to organizations that use Email Threat Detection and Response. The Click-time URL Protection service “rewrites” and performs checks on certain URLs in emails that are delivered to your organization’s end users. The process of rewriting allows the service to manage access to the URL to ensure the destination is innocuous.

This will need to be disabled to resolve the issue.

The Click-time URL Protection settings page is located in the portal at Email Threat Detection and Response > Click-time URL Protection Settings.

The Click-time URL Protection incidents are viewable on the Email Threat Detection and Response > Click-time URL Protection Incidents page of the portal.

 Further information can be found here. 

Marketo

We are aware that this happens with the Marketo package but there is no released fix as of yet.

Best thing to do is call them and find out how to get it disabled.

Hopefully this helps with the issues you are having, if not please log a support ticket.