Cannot load DeepL as a TM

Dear community, I've downloaded DeepL and added it to my project, added the API key but get the Error: Could not load file or assembly 'Newtonsoft.Json, Version+12.0........" I've seen on an earlier post that this might be due to installation issues, but Studio 2019 is working fine (I uninstalled 2017 before installing 2019). I'm wondering if there  is a conflict between the earlier DeepL plugin for 2017 and the newer version? TIA Elizabeth