How to schedule Instagram posts, Reels and carousels

Instagram's publishing API works only for professional accounts, meaning Business or Creator accounts. A personal account cannot be scheduled by any tool that publishes directly. Switching is free and done in the Instagram app's settings, and it can be switched back.

There are two ways a scheduler can connect. One goes through Facebook: the Instagram account is linked to a Facebook Page, and you sign in with the Facebook account that manages that Page. The other signs in with Instagram itself. Use whichever your tool offers; if you connect through Facebook and your Instagram account does not appear, it is usually not linked to a Page you manage, or it is still a personal account. Hookpost names this case directly: "Your Instagram account is not a business account, please convert it to a business account".

• Feed photos: the aspect ratio must be between 4:5 (portrait) and 1.91:1 (landscape). A 9:16 phone screenshot or a very wide banner is refused with "Aspect ratio not supported, must be between 4:5 to 1.91:1". Crop to 4:5, such as 1080x1350, for the most space in the feed.
• Reels: a single video in a post is published as a Reel. Export it vertically at 9:16, such as 1080x1920, as an MP4.
• Stories: images or videos, vertical 9:16. When a Story post has several items, each is published as a separate Story frame.
• Images should be JPEG. "Unsupported image format" or "Unsupported video format" means the file type is the problem, not the content.

A caption can be up to 2,200 characters; a longer one fails with "Caption is too long". Only the first line or two show under the post before "more", so put the point of the post there and the detail below.

Links in captions are not clickable on Instagram. Name the page in words, or put the link where your audience already looks for it, such as your profile.

If your tool supports a follow-up comment, as Hookpost does, you can publish a first comment right after the post. Some accounts use it to keep the caption short and put extra notes or hashtags underneath.

• A carousel holds between 2 and 10 photos or videos. Hookpost stops an eleventh item before scheduling with "Instagram carousel only supports up to 10 media attachments".
• Keep every slide the same shape, since the carousel shows all slides in one frame. Export them from one template at 4:5 or 1:1.
• Put the strongest image first; it is the only one shown in the grid.
• Collaborators cannot be added to a carousel. Instagram refuses it, and Hookpost reports "Collaborators are not allowed for carousel".

• Collaborators: a Reel or single post can invite up to three collaborator accounts, which must be public. The post appears on their profiles once they accept the invite in Instagram.
• Trial Reels: a Trial Reel is shown first to people who do not follow you, so you can test it without it appearing to your followers. It must be a single video; otherwise "Trial Reels can only have one video" or "Trial Reels must be a video". You can graduate it to your followers by hand, or let Instagram do it if it performs well. Not every account has Trial Reels; an account without them gets "This account doesn't support Trial Reels".
• Audio: music or an original sound from Instagram's library can be added only to a single-video Reel, not to Stories or carousels. You can set the volume of the added track and of the video's own sound.
• Cover: the scheduler sets the Reel's cover as a point in time in the video, so make sure the frame you want is in the video. If you want a designed cover, put it as the first fraction of a second of the video.

Like Pinterest, Instagram fetches the photo or video from a public address rather than receiving the file directly. It first builds a media container, processes it, and only then publishes. A video can therefore take a few minutes between the scheduled time and the post appearing. If the media host is slow, you will see "Timeout downloading media, please try again" or "Media fetch failed, please try again"; these are temporary and a retry usually works.

• Mix formats: a carousel, a couple of Reels and a photo post across the week rather than one format every day.
• Post once a day at most to start with, at an hour your audience is awake; Instagram's own insights show when your followers are active once you have some.
• Write each caption for its post. Copying one caption across Instagram, Facebook and LinkedIn reads as copied on all three.
• Look at the first post on your phone after it goes out, before the rest of the week publishes.

• "Something is wrong with your connected user, please re-authenticate" or a message about an invalidated session: reconnect the account. Instagram sometimes ends sessions after a burst of posting; Hookpost's advice in that case is to reconnect and wait a day or two before posting again.
• "Instagram detected that your post is spam, please try again with different content": change the caption and media rather than retrying the same post.
• "You have reached the maximum of 25 posts per day, allowed for your account": Instagram caps how many posts one account can publish through the API in 24 hours. Move some posts to the next day.
• "Instagram user is restricted" or "Instagram blocked your request": open the Instagram app; there is usually a notice there that only you can clear.
• "Not enough permissions to post": the connection was made without publishing permission, or it was removed in Meta's settings. Reconnect and approve every permission asked for.

Hookpost's Instagram integrations (through Facebook and through Instagram login): their validation rules (2,200-character captions, carousels of 2 to 10 items, single-video Trial Reels, audio only on single-video Reels, up to three public collaborators) and the error messages they map Instagram's responses to, read from their code on 13 November 2026, and the posts and Reels we publish through them. Hookpost is a product of the same team as HookStep.

• Instagram Platform: Content publishing, read 13 November 2026.

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