Two distinct errors can prevent your GBP automated posts from publishing to Google Business Profile: a "Must be a future datetime" rejection when a post sits unapproved past its scheduled date, and an "Image is not supported" rejection when a Media Library image exceeds Google's 5 MB limit. Identify which error you are seeing below and follow the steps to resolve it.
⚠️ Understanding the Two Error Types
Both errors occur inside the GBP Automated Posts workflow and block a post from reaching Google Business Profile. They have different root causes and different fixes.
- "Must be a future datetime" (HTTP 400) — The post's scheduled date passed before it was approved. Google rejects any post submitted with a past timestamp.
- "Image is not supported" — A Media Library image attached to the post exceeds Google's 5 MB file size limit. Google rejects the entire post, even if the image looks correct inside Search Atlas.
📅 Fixing the "Must be a future datetime" Error
Why this error occurs
When a GBP automated post enters Awaiting Approval status, it holds its original scheduled date. If the approver does not act before that date and time pass, the timestamp becomes stale. When you then approve the post, Search Atlas submits it to Google's API with that expired timestamp — and Google returns HTTP 400: "Must be a future datetime." The error message appears in the Status column of the Automated Posts table next to the affected post.
How to fix it
- Go to Local → Posts (GBP Posts).
- Locate the post showing the "Must be a future datetime" error.
- Click Edit on that post.
- Update the Scheduled Date and Time field to any date and time in the future.
- Save your changes, then click Approve.
Note: In some cases, posts pending approval may display as Scheduled rather than Awaiting Approval. If you cannot locate the post by status, search by post title or scheduled date instead.
The post submits successfully once its scheduled datetime is in the future.
🖼️ Fixing the "Image is not supported" Error
Why this error occurs
Google's Business Profile API enforces a strict 5 MB maximum file size for post images. When a GBP automated post uses a Media Library image that exceeds 5 MB, Google rejects the entire post with "Image is not supported" — even if the image previews correctly inside Search Atlas. The error message appears in the Status column of the Automated Posts table next to the affected post.
How to fix it
- Go to Local → Posts (GBP Posts).
- Locate the post showing the "Image is not supported" error.
- Click Edit and remove the current image from the post.
- Compress or resize the image to under 5 MB using a tool such as Squoosh or TinyPNG.
- Upload the compressed image to the Media Library or attach it directly to the post.
- Save your changes, then click Approve.
The post publishes successfully once the attached image is within Google's 5 MB limit.
💡 Preventing These Errors Going Forward
Avoid stale schedule dates
- Approve posts before their scheduled date passes — treat the scheduled datetime as a hard deadline for the approval action.
- When approval cycles are long, schedule the post further in advance to give reviewers enough lead time.
- Check the Awaiting Approval queue regularly so no post expires before it is reviewed.
Keep Media Library images within Google's size limit
- Before uploading any image to the Media Library for use in GBP posts, confirm it is under 5 MB.
- Target a minimum resolution of 720 × 720 px and a maximum file size of 5 MB — this satisfies both Google's quality requirements and size cap.
- Add image compression as a standard step in your GBP content preparation workflow to prevent failures at publish time.
🎯 You can now diagnose and resolve both the "Must be a future datetime" and "Image is not supported" errors in GBP Automated Posts — reschedule any post whose date has already passed, and compress any Media Library image above 5 MB before re-approving. For a full walkthrough of configuring GBP Automated Posts, see the GBP Automated Posts Overview article.