I cannot connect to my jira cloud system due to invalid user data.
The user data are 100% correct.
Do I need to authentificate in a different way?
This is "Unauthorized (401)" error which means that incorrect login or password is used.
Jira API was recently updated and it is required to use an API token for successful connection.
In order to connect to your Jira instance, you need to specify your Domain, your email address and generate a token at https://id.atlassian.com/manage/api-tokens and use it as a Password.
Please tell us if this information helps.