Use a public https:// link to a supported file type in each media step.
Send an image, video, document or audio steps send a file WhatsApp downloads from your link. The link must start with https:// and, when it ends in a file extension, be a type WhatsApp accepts: .mp4 or .3gp for video; .pdf, .doc(x), .xls(x), .ppt(x), .txt or .csv for documents; .aac, .amr, .mp3, .m4a, .ogg or .opus for audio.
Upload the file somewhere public that serves it over https.
Paste the direct link to the file, then save again.
Still stuck? Send AVX-3291 to hello@theavoxai.com along with what you were doing when it happened.