This was my solution / workaround
In de databse table “plugin_integration_settings” I copies the content of the three fields into a .tct file and saved it. I disabled the plugin by replacing the 1 with 0 in field is_published.
I replaced the content in the next fields with:
supported_features
a:2:{i:0;s:9:“push_lead”;i:1;s:9:“get_leads”;}
api_keys
a:0:{}
feature_settings
a:0:{}
Save the changes in the database by clicking go.
Next go into Mautic plugin hubspot and add the key and save.
I got a 500 error again but by savin& closing and reopening again i progressed step by step.
Then I went back to the database and put the old content back of field Feature setting. (restoring fieldmappings.
Now in hubspot at the private app I see API calls.
What I did find strange is that in de Gitpod Dbase the ID of hte Hubspot plugin differs from my database. Furthermore in the Gitpod database there are two tables for Hubspot (And other plugins)