What each platform will and will not accept

Instagram always needs an image — the most common reason a share does not work — plus per-channel length limits and why one failure does not block the rest.

• Instagram always needs an image. It has no text-only posts, so a listing with no image cannot be posted there. Add an image, or choose another channel. This is the single most common reason a share to Instagram does not work.
• Every channel has its own limits. Long descriptions are shortened to fit the platform rather than rejected.
• A failed post does not fail the others. Channels are published to independently, so one broken connection does not hold up the rest.