Printing a label to a DYMO label printer shows a drop down to select a printer with no option or old printers available.
DYMO uses a service called the DYMO Web Service to print labels from websites, such as eVetPractice. The printer option is usually presented when the service is not running.
Reboot the computer to restart the webservice.
Open the Dymo Label v.8 Software and make sure a printer is recognized > select "Print" to test.
Verify that all printers showing in Windows printers and scanners are still valid. If not remove as needed, and restart the DYMO Web Service.
If the issue still persists see this DYMO support article to remove the DYMO drivers from the workstation.