It seems like there must be some theme/plugin conflict on your end and hence you are facing this issue. Just to be sure, deactivate all the plugins except WooCommerce, MultiVendorX and MultiVendorX Pro on your end and also switch to some default theme such as twenty twenty three or storefront and check again.
If this resolves the issue then kindly enable the deactivated plugins one at a time to identify the culprit.
Also please do keep us posted regarding the same.