Failed Enabling Lost Mode. Unable to enable Lost Mode

I lost my AirTag. I’m able to locate it about 400m away, but I can’t activate lost mode to leave my phone number.. Instead I get the following message:

Failed Enabling Lost Mode

Unable to enable Lost Mode

Yet when I select 'email' for notification it is successful. I reported this to the Apple chat line and they escalated it to a more senior engineer who in turn escalated to the most senior , senior engineer.

This problem is now with the software update coders and they will get back to me when there is a solution.

By the way , the lost item (cat) has turned up now !