As of version 2.3.5 Commerce Edition, Magento implemented new feature called Category Permissions (https://docs.magento.com/user-guide/catalog/category-permissions.html).
Category access can be limited to specific customer groups, or restricted entirely. You can control the display of product prices, and determine which customer groups can add products to the cart, and specify the landing page.
Error displayed when category page is restricted:
[2020-07-07 17:23:06] report.CRITICAL: You may need more permissions to access this category. {"exception":"[object] (Magento\\Framework\\Exception\\LocalizedException(code: 0): You may need more permissions to access this category. at /srv/xxxxxxxxx/releases/20200707154013/vendor/magento/module-catalog-permissions/Observer/ApplyCategoryPermissionObserver.php:113)"} []
[2020-07-07 17:23:06] report.CRITICAL: You may need more permissions to access this category. {"exception":"[object] (Magento\\Framework\\Exception\\LocalizedException(code: 0): You may need more permissions to access this category. at /srv/xxxxxxxxxx/releases/20200707154013/vendor/magento/module-catalog-permissions/Observer/ApplyCategoryPermissionObserver.php:113)"} []
How To Disable Category Permissions:
php bin/magento config:set catalog/magento_catalogpermissions/enabled "0" --lock-config
Or add following to the env.php or config.php files:
'system' => [
'default' => [
'catalog' => [
'magento_catalogpermissions' => [
'enabled' => '0'
]
]
]
]
For security reasons, there is no on / off switch available from the Magento admin panel (otherwise a potential attacker with Magento admin access could disable it easily). As such it must be done from the command line.
Hope this helps. Good luck!