Submission limit reached

When your review limit is reached, back off and work on other projects.  Wait for the current batch to be reviewed.

Read the first pinned post in this Stock Contributor forum which relates to the fact that weekly submission limits have been established for all accounts. 

Even if you have no assets in the "in review" tab, your Submit button will be grayed out if you reached the max submission limit for your account in the prior week. We don't know yet when the week starts, but it's possible that it will reset in the next day or so because the systemwide change was announced on May 20th.

Check here: https://community.adobe.com/t5/stock-contributors-discussions/new-submission-limits-for-adobe-stock-contributors/td-p/15330817

The message posted by AdobeStock on Discord is as follows:

We’re introducing updated submission limits for Adobe Stock Contributors to help maintain the strength and quality of our growing collection. These updates support the continued success of both our Contributor community and customers alike. When you reach your weekly submission limit or the maximum amount of allowed content pending moderation, you will experience a temporary pause before you can submit additional content.

I don't know the exact upper limit.

The new submission limits have not been made known. We cannot help. Just keep trying.