No, the Twitter API currently does not allow tweets longer than 280 characters, even if you have a Twitter Blue subscription. This functionality is limited to Twitter's web and mobile interfaces, not through the API.

The 'Rate limit exceeded' error occurs when the usage limit set by the Twitter API for the number of tweets that can be posted within a specific time period is reached. Twitter imposes restrictions on the number of tweets that can be sent per day and per month, depending on the account type and access level.

If you encounter this error, it means that you have exceeded the allowed limit of tweets within the corresponding time period. For detailed information about usage limits and restrictions, you can visit the following link: https://developer.twitter.com/en/portal/products/free.

If you need to post more tweets than the limits established, you may want to explore premium subscription options offered by Twitter to increase your usage limits.

To send messages and direct messages, Twitter requires you to enable the 'write' permission in its API. In this video, you have all the steps to configure the API in read and write mode.

This error from X may be due to several factors, many of them related to the content of the tweet you are trying to post. A common example is when the tweet contains URLs that do not meet the proper format or structure according to Twitter's policies.
To resolve this issue, it is recommended to review and modify the tweet's content. Try simplifying it or changing the URLs to ensure they comply with X's requirements.