Unable to clear message storage

sadie_laine,

Do you use Messages in iCloud on any other device? If so, that iCloud storage is shared. Check out the section "Delete texts and attachments in Messages" in the 'Manage your iCloud Storage' article shared by Trish313.

Additionally, if you have a computer you can connect your iPhone to view storage details and compare the information to what you see in Settings > General > iPhone Storage. The section "Use the Finder or iTunes to check the storage on your iOS device" from the article here has steps if needed. How to check the storage on your iPhone, iPad, and iPod touch

However, with iCloud it may take some time for the removed data to reflect correctly in your overall storage. Be sure your iPhone is connected to a known working Wi-Fi network. Connect to Wi-Fi on your iPhone, iPad, or iPod touch and if there's no update after 24/48 hours reach out to Apple Support directly to further assist.

Contact Apple Support

Best!

Hi sadie_laine,

Thank you for posting in Apple Support Communities! Since deleting items from your storage, has your iPhone been restarted? Looks like you have an iPhone XS tagged in your post, to reset that model you'll want to press and hold one of the volume buttons and the side button until the power-off slider appears. Once powered off, you'll want to wait about 30 seconds and then power it on.

Restart your iPhone

Check out how to make more storage available here: Manage your iCloud storage

Hope that helps!