Certain attachments are blocked by Elements Collaboration Protection due to disallowed content.

Issue:

We have certain email attachments are blocked by Elements Collaboration Protection due to disallowed content. The files are clean and how do we solve it?

Resolution:

To resolve the blocked attachment due to the "Disallowed content" verdict, you can either allow the file extension or add the trusted sender email address/domain to the tenant's policy.

To allow the file extension:
a) Log on to the WithSecure Elements portal (https://elements.withsecure.com/)
b) Go to Collaboration Protection > Policies
c) Select the tenant's policy
d) Go to General > Malware scanning
e) Click on the drop down menu, and untick the target file type
f) Click Save

Add the sender address/domain to exclude attachment scanning:
a) Log on to the WithSecure Elements portal (https://elements.withsecure.com/)
b) Go to Collaboration Protection > Policies
c) Select the tenant's policy
d) Go to Exchange > General
e) Turn on the 'Trusted senders' option
f) Add the sender email address or domain
g) Click Save

https://www.withsecure.com/userguides/product.html#business/fse4ms365/latest/en/task_7177D009B59245F38D9051D201AF825E-latest-en