Mautic fix mail derivering problem

Hello, we are using Mautic for the Email Marketing campaign, we use it with an SMTP. We have tested the sending of each email individually and it works correctly, they reach the test emails that we place. However, when we try to add a contact to the campaign, it stays with the title "Pending" and never arrives. If you have experience solving this type of error or it has happened to you, your solution will be of great help. 1 These are a couple of forums where the topic is discussed, but I need a solution. [login to view URL] [login to view URL] 2 The message "This field is required" does not appear on the form when a person leaves a mandatory field empty. Here are a couple of posts about it: [login to view URL] [login to view URL] 3 Mautic is running in OVH server, Mautic must run in [login to view URL] but don´t works. Mautic just works in a number IP URL. We need Mautic runs ok in [login to view URL] and we need that Mautic Landing Pages runs with the URL [login to view URL] An user is in [login to view URL], when the user tries to download the ebook the Download Landing Page is a numbers IP URL. It is not good. Thank you.