Hi @Sohaib Aumer
You may want to try opening a ticket with Zapier Support: https://zapier.com/app/get-help
Wonder if it is related to this recent Zapier incident: https://status.zapier.com/incidents/y7t2sqxhpdmv
Hi there, @Sohaib Aumer 
Just came across this and wanted to check how you’re getting on. I couldn’t find any open Support tickets from you about this, was it related to the incident that Troy mentioned? Or did you manage to find a workaround to publish the Zap?
If you did find a fix, would you be up for sharing what it was?
If it’s still not published, I wonder if it could be a bug.
I found a similar report of this for dynamically selected channels weren’t allowing the Zap to be published. In that case:
When the media type is "image" or "multiple_images" i can save the zap and publish it. BUT, when the media type is "video" and post type is "reel"
When the Support team looked into the Zap it had since been published successfully and the person never replied so I’m not sure what resolved the issue.
From your screenshots it looks like you might be using the videos as well. If you have the Channel ID mapped from the Formatter step but pass an image instead of a video does that allow you to publish the Zap successfully, or does it give the same error?
Looking forward to hearing from you on this!