Instagram has strict requirements on what can be auto posted, which Planoly has no control over.
Please review Instagram's restrictions on auto posting: Auto-Posting to Instagram FAQ
* Most Portrait/Landscape images do not qualify for IG direct publishing.
* - Crop them more into a square, and they should be eligible for auto posting.
* Stories, Multi-Image Posts, Drafts, Shopping Tags, Branded Content Tag Filters do not qualify for auto post.
Maximum File Size: 8MB
Image Types Accepted: JPEG, PNG, BMP, and non-animated GIFs
Image Ratio Specifications: Images must be within a 4:5 to 1.91:1 aspect ratio range Minimum Resolution: 150x150 (lower resolutions will be scaled up to the minimum)
Maximum Resolution: 1920x1080 (higher resolutions will be scaled down to the maximum)
Previous posts scheduled before you enabled auto post will not directly publish to Instagram. You can simply go back to those scheduled posts and adjust the time +/- 1 minute for auto post to be enabled.