Frequent posting errors & troubleshooting by social network

This error indicates that you do not have sufficient permissions to post. Remember that you need super administrator permissions. You can easily check this within LinkedIn by going to the top right "Me" menu > Click on the company name > Settings > Manage Admins.

This error indicates that LinkedIn cannot access the image associated with the link included in the copy. Although the preview in Metricool may display the image correctly, LinkedIn is unable to retrieve it when processing the URL, so the final post may appear without an image.

You can check this using LinkedIn's official tool: https://www.linkedin.com/post-inspector/
When analyzing the URL, LinkedIn will show the field Image: No image found.

Keep in mind that previews are an approximation of how the post will look. The final result may differ.

This error means you have reached your posting limit on Metricool for YouTube. Keep in mind that these limits are per 24-hour period, not by calendar day.

• FREE Plan: 10 posts every 24 hours

• Premium Plan: 20 posts every 24 hours.
  To check if you can post, count the last 24 hours from the current time; if there are fewer posts than the set limit, you can post.

This warning (the video is published) means the account doesn't have the feature enabled to set custom thumbnails when uploading via the API. The channel owner needs to verify the YouTube account and make sure the "custom thumbnails" option is turned on. You can check the details here.