Error in activation of the model application

What product/components do you use and which version/fix level are you on?

latest

Is your question related to the free trial, or to a production (customer) instance?

production

What are you trying to achieve? Please describe it in detail.

Do you get any error messages? Please provide a full error message screenshot and log file.

Unable to actiavte the model that was deactivated yestersay.

Have you installed all the latest fixes for the products and systems you are using?

yes