Hello,
First of all thanks for choosing our Theme, we are glad to be you in the WoodMart WordPress family :-)
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In most cases, this issue may be connected to the PHP max input vars limit parameter in your web server configuration. You can check the current value for this parameter in your Dashboard -> WooCommerce -> System status. Usually, this parameter is not allowed to be changed on shared hostings so you will need to contact your service providers and ask to increase this limit. The recommended value for this is 10,000
Best Regards.