Short answer: You can send DMs on Facebook and Instagram only, with the DM inbox (Pro plan or higher, or during your free trial), and only inside the time window that Meta allows after the person's last message. If you see This message is sent outside of allowed window., that window has passed. If the inbox stays empty or you can't reply on Instagram, check Instagram's message settings and conversation routing (section 3).
1. Channel, plan and permission
Channel. DMs work on Facebook Messenger and Instagram. TikTok does not offer DMs through its API (replient.ai shows: Currently the TikTok API is not supporting sending direct messages). LinkedIn, YouTube and review platforms have no DMs in replient.ai either.
Plan. The DM inbox is part of Pro, Business and Enterprise, and of the free trial. It is not part of Lite. Without it, the Messages page shows an upgrade dialog (Unlock the … Feature "DM Inbox") and sending fails with Inbox access is required to send messages. See Which plan is right for me?.
Team permission. To send DMs, your team role needs Manage messages. Otherwise you get You do not have permission to manage messages for this brand. Ask the account owner to change your role.
Influencer partners. For partnership posts, replient.ai never sends DMs on the influencer's behalf. The message is Can't send a DM on the influencer's behalf.
2. "This message is sent outside of allowed window."
Facebook and Instagram only let a business message a person who has written to it recently. Meta sets this time window, not replient.ai, and replient.ai can't extend it. Typical situations:
The person wrote to you a while ago. Wait until they write again – any new message from them reopens the window. You can reply to their public comment and invite them to message you.
Private message from a comment. You can send one private message per comment and only within 24 hours after the comment: You can only send a private message within 24 hours after the comment.
A second automated DM before the person answered. After a comment, Facebook and Instagram accept exactly one DM until the person replies. The automation editor warns you: Instagram and Facebook won't deliver a second message before the user replies, so this step will fail. Add a question or a wait-for-reply step before the next message, or remove it. See Why didn't my DM Automation trigger?.
A message that failed because of the window is not sent later automatically. The person has to write to you first.
3. Instagram messages are switched off or go to another app
Instagram message settings
If Instagram has turned off access for connected tools, replient.ai cannot load or send DMs. On the Learning page a yellow warning appears: Your Instagram accounts messaging is disabled for API. We cannot load your conversations. To fix it:
In the Instagram app, open your professional account and go to Settings and activity → Messages and story replies → Message controls → Connected tools.
Switch on Allow access to messages.
Back in replient.ai, click the refresh icon (Check again) in the yellow warning. You see Yay! We can load your conversations now. If you see We are still unable to load your conversations. Please try again or reach out to support., check the setting again or contact us.
A video walkthrough is in How do I set up Conversation Routing for Instagram?.
Conversation routing
Only one app can control the conversations of your Instagram account or Facebook Page. If another tool is the default (for example ManyChat, Meta Business Suite or another CRM), replient.ai does not receive messages and can't reply. Set replient.ai as the default app and make sure the connected-app toggles in Advanced messaging are on:
4. The message itself
Message | What it means | What to do |
Facebook only allows messages up to 640 characters | Facebook limits the length of a DM. | Shorten the message or split it into two. |
Instagram only allows messages up to 1000 characters | Instagram limits the length of a DM. | Shorten the message or split it into two. |
Invalid file type – Only images and videos are supported | You attached another kind of file. | Send an image or a video. |
File too large – File size should be less than 8MB / 25MB | Images can have up to 8 MB, videos up to 25 MB. | Compress the file. |
Some content failed to send | The text was sent but an attachment (or the other way round) failed. The reason is shown below the title. | Send the missing part again. |
Failed to send message | The platform rejected the message. The reason is shown below the title. | Look it up in this article. For other reasons see What do the error messages mean when I reply, like or hide a comment?. |
Messages with buttons can have up to 3 buttons, each with up to 20 characters of text.
5. Connection and conversation problems
Message | What it means | What to do |
Access token expired. Please refresh the token from learnings page | Your Facebook or Instagram connection is no longer valid. | Open Learning, click the three dots on the channel and choose Reconnect. |
The thread owner has archived or deleted this conversation, or the thread does not exist | The person deleted or archived the chat on their side. | You can't send to this conversation any more. Wait until they write again. |
Running automation for this conversation | A DM automation is currently running for this person. | Click Stop Automation if you want to take over. See Can I stop a running DM automation for a specific contact. |
Bulk action running for this conversation | A bulk action is still processing this conversation. You can't interact with it until it is done. | Wait until the bulk action finishes. |
You can always answer in the app itself: open the conversation and click Open conversation on Instagram or Open conversation on Facebook.
Still not working?
Send us a message in the chat with: the platform, a link to the conversation in replient.ai, the exact error message, and when the person wrote last. A screenshot of your Learning page helps too.