I was able to link to x, but can’t post.

I have linked my account with x by ensuring that the following rules are followed.

1. Sign up for a X/Twitter developer account
Click on "Sign up for Free Account" button to proceed with free access.
Fill out the Describe all of your use cases of X's data and API field. You can find an example response below.
I am planning to add an auto-post feature on my WordPress website with the help of the Autopost for X, WordPress plugin. Whenever a new post will be published on the website, Autopost for X plugin will use the post data to curate and trigger a Post.
Click on "Submit" button, it will redirect you to Developer portal.
2. Configure access to your X/Twitter app access tokens
Go to the X/Twitter developer portal
Click on Projects & Apps on the left navigation menu.
Find the App and click it to show the Settings page for the App.
Click "Setup" under User authentication settings to setup Authentication.
Enable OAuth 1.0a and Set App permissions to Read and write.
Set the Website URL to https://example.com.
Set the Callback URLs fields to https://example.com/wp-admin/admin-post.php?action=authoshare_authorize_callback and click Save.
Switch from the "Settings" tab to the "Keys and tokens" tab.
Click on the Generate/Regenerate button in the Consumer Keys section.
Copy the API Key and API Key Secret values and paste them below.
3. Save settings
Click the Save Changes button below to save settings.
4. Connect your X/Twitter account
After saving settings, you will see the option to connect your X/Twitter account.
Click the Connect X/Twitter account button and follow the instructions provided there to connect your X/Twitter account with this site.

Then I submitted the article.
Then the following notification appeared in the sidebar.

Does anyone know the cause of this?
If you know something, it would be great to know.
Thank you in advance.