Generic connection error during integration with Woocommerce

Unfortunately we are no longer able, on our main server, to establish the connection with the plugin ActiveCampaing following the procedure. We have a 1:1 copy of the entire site in a staging area on a different server and we do not find any anomalies. The problem that occurs on the site in the production environment is the following: when the integration is created, the system responds with a generic connection error. Going deeper, we obtained the link of the call using the site under test and we verified that, if we force the url below, the site in production also shows the authentication screen; obviously the process fails and ends with a permission error. what can we test in order to complete the link procedure to activecampaing? The url called in the procedure seems to be: https://www.emmebiitalia.com/wc-auth/v1/authorize?app_name=ActiveCampaign&scope=read_write&user_id=d7263fa56b45c83cc5425e78880126b1978ffb00&return_url=https%3A%2F%2Fteam-ecommerce-deep-data.cluster.app-us1.com%3A443%2Fauth%2Fwoocommerce%2Fcomplete&callback_url=https%3A%2F%2Fteam-ecommerce-deep-data.cluster.app-us1.com%2Fauth%2Fwoocommerce

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