Hi @Alvaro_RS
Only running office 365 scope will not confirm that the details are correct. Even if you give A B and C in your appID secret and Tenant ID it would still run with out throwing error.
The scope gets executed only when there is an activity inside it
So Please cross verify the same
And do one thing… Run the bot in debug mode and when you get the error open the locals panel and check the inner exception details that might give more information on why the access is denied
Alternately instead of application secret can you try using username and password .We are actually using integrated or username and password and never faced an issue
Cheers