Your guestbook may be full. You'll need to free up space in your guestbook before visitors can sign it again.

To free up space in your guestbook:

1. Go to the Create & Update tab of your GeoCities Control Panel and click the "Add-Ons" link.
2. Under "Visitor Feedback Tools," choose "Guestbook."
3. In the "Guestbook Manager" section, choose "Current Posts." Here you can choose to delete or archive your posts.

To delete old or unwanted guestbook entries:

1. Check the box next to each post you want to delete.
2. Choose "Finished."

To archive your guestbook entries:

1. Go to the Create & Update tab of your GeoCities Control Panel and click the "Add-Ons" link.
2. Under "Visitor Feedback Tools," choose "Guestbook."
3. You'll see a column called "Guestbook Manager" on the left side of the page. Click the "Current Posts" link.
4. Click the "Archive" button. This will create a file that is a copy of all of your current guestbook posts.
5. Enter a name for this new file, such as archive.html. Make sure that you include the .html extension when naming this file.
6. You'll arrive on a confirmation page. Click the "Current Posts" link to review current posts.

Once you've saved your posts to an archive file, you should delete your old posts. To review your archive, return to File Manager and click the "View" link next to the name of the archive file you created.