Hi Neto,
Thank you for the details!
When I am logged out I get the same error message on both desktop and mobile. The error response reveals this message from your server: https://i.imgur.com/Ohxkc2J.png
This means, that a firewall/server policy is blocking the requests to the wordpress ajax handler. If you use any firewall/fence plugins, check the firewall configuration. It is more likely coming from the actual server or CDN, you may have to check the firewall on that end as well.
There is a ray ID you can refer to for a block to filter further requests: RID: GCUQZ346G2S8KVREXVD0BWLC
