Thanks @Oneric , that helps! Especially as there’s nothing I need to do 
As far as the last one is concerned, it’s a rather long one, and it’s the only PeerTube account I follow:
akkoma-app | 15:30:07.172 [info] Received invalid AP document: {:error, #Ecto.Changeset<action: :insert, changes: %{id: "https://makertube.net/videos/watch/cb6fa58d-4981-4a4b-9a28-8af37d40f271", name: "Tschüss, USA: Europäische Alternativen", type: "Video", context: "https://social.zell-mbc.com/contexts/20ce7945-102a-42a2-ad19-23f4777efc25", cc: ["https://makertube.net/accounts/ct_3003_channel/followers"], to: ["https://www.w3.org/ns/activitystreams#Public"], url: "https://makertube.net/w/r82zDAKQPtDRAFhKfwUsMp", actor: "https://makertube.net/accounts/ct_3003_channel", published: "2025-03-21T17:42:07.958Z", content: "<p>=== Anzeige / Sponsorenhinweis === Sichere dir 4 EXTRA-Monate auf ein 2-Jahresabo über <a href=\"https://nordvpn.com/ct3003\">https://nordvpn.com/ct3003</a>. Teste NordVPN jetzt risikofrei mit der 30 Tage Geld-Zurück-Garantie. === Sponsorenhinweis Ende === ► Wie sich dieser Channel finanziert: <a href=\"https://www.youtube.com/watch?v=xWLRoMP3rLU&t\">https://www.youtube.com/watch?v=xWLRoMP3rLU&t</a> </p><p>Dieses Video geht an alle, die sich mal mit europäischen Alternativen zu großen US-Diensten wie Google, Meta, Microsoft oder Apple beschäftigen wollen.</p><p>► Alle Links aus dem Video:</p><ol><li><p>E-Mail-Anbieter: • Tutanota: <a href=\"https://tutanota.com\">https://tutanota.com</a> • ProtonMail: <a href=\"https://protonmail.com\">https://protonmail.com</a> • Posteo: <a href=\"https://posteo.de\">https://posteo.de</a> • Mailbox.org: <a href=\"https://mailbox.org\">https://mailbox.org</a> • GMX: <a href=\"https://www.gmx.net\">https://www.gmx.net</a> • Web.de: <a href=\"https://web.de\">https://web.de</a></p></li><li><p>Suchmaschinen: • Ecosia: <a href=\"https://www.ecosia.org\">https://www.ecosia.org</a> • Qwant: <a href=\"https://www.qwant.com\">https://www.qwant.com</a> • Startpage: <a href=\"https://www.startpage.com\">https://www.startpage.com</a> • Good Search: <a href=\"https://www.good-search.org\">https://www.good-search.org</a></p></li><li><p>Karten- und Navigations-Apps: • Here WeGo: <a href=\"https://wego.here.com\">https://wego.here.com</a> • Sygic GPS Navigation: <a href=\"https://www.sygic.com\">https://www.sygic.com</a> • TomTom GO Navigation: <a href=\"https://www.tomtom.com\">https://www.tomtom.com</a> • OsmAnd: <a href=\"https://osmand.net\">https://osmand.net</a> • Organic Maps: <a href=\"https://organicmaps.app\">https://organicmaps.app</a></p></li><li><p>Messenger: • Threema: <a href=\"https://threema.ch\">https://threema.ch</a> • Olvid: <a href=\"https://olvid.io\">https://olvid.io</a> • ginlo: <a href=\"https://ginlo.net\">https://ginlo.net</a> • SKRED: <a href=\"https://skred.mobi\">https://skred.mobi</a></p></li><li><p>Kollaborations- und Office-Lösungen: • Nextcloud: <a href=\"https://nextcloud.com\">https://nextcloud.com</a> • kSuite von Infomaniak: <a href=\"https://www.infomaniak.com\">https://www.infomaniak.com</a> • CryptPad: <a href=\"https://cryptpad.fr\">https://cryptpad.fr</a> • Jitsi Meet: <a href=\"https://meet.jit.si\">https://meet.jit.si</a> • OpenTalk: <a href=\"https://www.opentalk.eu\">https://www.opentalk.eu</a> • Stackfield: <a href=\"https://www.stackfield.com\">https://www.stackfield.com</a></p></li><li><p>Soziale Netzwerke: • Mastodon: <a href=\"https://joinmastodon.org\">https://joinmastodon.org</a> • Pixelfed: <a href=\"https://pixelfed.org\">https://pixelfed.org</a> • BeReal: <a href=\"https://bere.al\">https://bere.al</a> • Xing: <a href=\"https://www.xing.com\">https://www.xing.com</a></p></li></ol><p>► DER 3003-HYPE-NEWSLETTER: <a href=\"https://ct.de/hype\">https://ct.de/hype</a></p><p>► Alle Newsletter von Heise: <a href=\"https://www.heise.de/newsletter/\">https://www.heise.de/newsletter/</a></p><p>► Hier geht es zum c’t-WhatsApp-Kanal: <a href=\"https://whatsapp.com/channel/0029VaCU\">https://whatsapp.com/channel/0029VaCU</a>…</p><p>► Keno auf Instagram: <a href=\"https://www.instagram.com/elektroelvis/\">https://www.instagram.com/elektroelvis/</a></p><p>► c’t Magazin: <a href=\"http://ct.de\">http://ct.de</a> ► und TOTAL CRAZY auf Papier! Überall wo es Zeitschriften gibt!</p><p>► Credits: Konzept & Redaktion: Jan-Keno Janssen, Lukas Rumpler Schnitt: Sahin Erengil Host: Jan-Keno Janssen</p><p>#DigitaleSouveränität #EuropäischeAlternativen #Datenschutz</p>", updated: "2025-03-25T14:59:05.095Z", attributedTo: "https://makertube.net/accounts/ct_3003_channel"}, errors: [tag: {"is invalid", [validation: :embed, type: {:array, :map}]}, attachment: {"can't be blank", [validation: :required]}], data: #Pleroma.Web.ActivityPub.ObjectValidators.AudioVideoValidator<>, valid?: false, ...>}
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