Could be related to the core Stripe payment gateway plugin https://wordpress.org/support/topic/fatal-error-in-version-5-5-0. There is a fatal error when WC Admin is disabled.
@pipdig Yes, it can be related with such issue because I have Stripe gateway 5.5.0 installed also. Meanwhile it is solved I keep this plugin disabled.
@ospiotr thanks for your help.
Stripe plugin + this plugin = Fubar
Dear @anchises @ambrosio992
This issue will be fixed in an upcoming update of WooCommerce Stripe Payment Gateway
plugin: https://github.com/woocommerce/woocommerce-gateway-stripe/pull/1924
Thanks, I won’t upgrade the Stripe payment plugin until further notice.