Increase the maximum upload file size for your WordPress Multisite using the steps below.
By default, WordPress Multisites are limited to a maximum of 1.5MB for file uploads. This can cause filename exceeds the maximum upload size for this site. error messages when you upload a file on your site.
Increase WordPress Multisite Upload Size
- Log in to your WordPress Dashboard.
- Select My Sites > Network Admin > Dashboard from the menu.
- Click Settings > Network Settings
- Scroll down and change Max upload file size to your preferred upload size.
- Click Save Changes