no size limits, we have a dedicated server
could it be a conflict with a plugin?
Installed plugins
Dvin Woocommerce Wishlist by Kiran Polapragada version 1.3.3,
Easy Contact Forms by wppal version 1.4,
GD Star Rating by Milan Petrovic version 1.9.20,
Jetpack by WordPress.com by Automattic version 1.7,
Remove “Comments are closed” by Per Soderlind version 1.2,
Scroll popup html content ads by Gopi.R version 4.0,
Smart Manager for e-Commerce by Store Apps version 2.7,
SYN Media WooCommerce Rewards by SYN Media Inc. version 1.1.3,
Usernoise by Nikolay Karev version 2.0.4,
WangGuard by WangGuard version 1.5.1,
WooCommerce Print Invoices & Delivery Notes by Steve Clark, Triggvy Gunderson, David Decker version 1.4.4,
WooCommerce Dynamic Gallery PRO by A3 Revolution Software Development team version 1.0.2,
WooCommerce Email Inquiry & Cart Options PRO by A3 Revolution version 1.0.0,
WooCommerce Pro Shipping by Lee Willis version 1.3.3,
WooCommerce Predictive Search PRO by A3 Revolution Software Development team version 1.1.1,
WooCommerce by WooThemes version 1.6.5.2,
WordPress Backup to Dropbox by Michael De Wildt version 1.2.2,
WordPress SEO by Joost de Valk version 1.2.8.4,
WP Robots Txt by Christopher Davis version 1.0,
WP SlimStat by Camu version 2.8.3,
WP to Twitter by Joseph Dolson version 2.4.9,
XML Sitemap Feed by RavanH version 3.9.2