Unable to install all activities in Uipath

I have been trying to install Uipath multiple time but I am still getting errors as given below:

Failed to load assembly: C:\Users\amitd.nuget\packages\uipath.mail.activities/1.8.5\lib/net461/MimeKit.dll
Failed to load assembly: C:\Users\amitd.nuget\packages\uipath.mail.activities/1.8.5\lib/net461/UiPath.Mail.Activities.dll
Failed to load assembly: C:\Users\amitd.nuget\packages\uipath.mail.activities/1.8.5\lib/net461/UiPath.Mail.dll
Failed to load assembly: C:\Users\amitd.nuget\packages\uipath.system.activities/20.4.0\lib/net461/UiPath.OrchestratorClient.dll
Failed to load assembly: C:\Users\amitd.nuget\packages\uipath.system.activities/20.4.0\lib/net461/UiPath.System.Activities.dll

I do not know how I may resolve this issue, since I am unable to get access to Mail or Data extract wizard, and many others. DO let me know what the cause for this error, since I have uninstalled and re0installed the solution muktiple times.
regards
Amit