CM250 FAQs & Troubleshooting CM250 Not your product? Sort by Updated Date Popularity 3 Results 1. 01/22/2020 “The entered text cannot be used.“ appears on the computer screen. 2. 01/22/2020 List of Error Messages for CanvasWorkspace (Others) 3. 03/11/2019 "Please register your machine." appears on the computer screen. Error Messages FAQs & Troubleshooting