Most likely culprits:

1. If you have a firewall running ... you need to "tell it" to allow access to our site.
2. You may have your browser's security/privacy settings too restricted, which won't permit attachments to open. Adjust the settings to allow less restriction on this site.
3. If you have ad-blocker software installed, this will prevent attachments from opening. YOu should be able to temporarily disable it to allow opening the attachment file.

hth,

Doreen