You may be getting an intermittent 401 error response when making a call through K2 - REST API to UiPath.
The issue could be caused by the UiPath OAuth tokens expiring after 30 minutes. K2 refreshes the token after 60 minutes by default.
Increasing the UIPath token lifetime to above 60 minutes will resolve the issue.
Update the UiPath web.config, add the following setting in the AppSettings section and set “Auth.Cookie.Expire" to 70 as follows:
<add key="Auth.Cookie.Expire" value="70" />
<add key="Auth.Bearer.Basic.Expire" value="70" />