Error Uploading to Forum

[potga]

Get the following error when I try and upload a Untitled.png.xls file

What am I doing wrong?

[potga]

Maybe this will show the error
Untitled.png

[alansidman]

Are you using the following procedure?

Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.

[potga]

Using Manage Attachments.
Tried to attach the error but now getting a page 'Sucuri WebSite Firewall - Cloud Proxy- Access Denied' so cannot attaché anything