I have had an answer from Support which I hope someone else may find useful in the future:

Regarding the issue you're facing, it appears that the maximum number of versions allowed for this file (1000) has been reached. You can find this and other CLM service limits at: https://support.docusign.com/s/document-item?language=en_US&bundleId=pxt1643324456371&topicId=woi1737643109961.html&_LANG=enus

To resolve this, please follow these steps:

1. Locate the "Providers.csv" file in your folders and download this file to your computer.
2. Rename the existing "Providers.csv" file in the folder to something different, such as "Providers_archived.csv".
   • Mark the checkbox on the left side of the file name.
   • Select "File > Rename" from the top menu.
   • Enter the new name and save your changes.
3. Upload the copy of "Providers.csv" that you just downloaded back to the same folder, using the original file name (Providers.csv).
4. Confirm that the new file appears in the folder with the correct name, "Providers.csv".

As each file contains its own internal ID, this procedure will make CLM treat the "Providers.csv" as a newly uploaded file and assign it version 1.0.

If you constantly adding to this file then you’ll continue to get this error after 1000 versions.  To remedy this you need to create an attribute to track versions (ie, version number).  Create a workflow that increments this attribute each time there’s a new record.  Once the attribute value reaches 999 create steps that moves or renames the file, then have the workflow create a new file with the Attribute (Version Number).  The process would repeat automatically so you don’t have to manually keep track and move.