Unable to send large attachments

Hello,

I am having an issues similar to this when trying to attach large files.

Here is the code for the attachment: [file* your-file limit:5mb filetypes:csv|spx]

Small csv files send fine. When I attempt to send an spx file around 3MB, I get a red error box saying

Failed to send your message. Please try later or contact the administrator by another method.

I have the max upload of my site set to 1024MB by editing my php.ini with post_max_size=1024M and upload_max_filesize=1024M. Also, I modified web.config to contain

<security>
<requestFiltering>
<requestLimits maxAllowedContentLength?=”1073741824″/>
</requestFiltering>
</security>

.

Is there anything I am missing?

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