Okay so for those with the same problem.. it's possible to fix on 1.74.3 (Current version of Cloudron) by following these steps:
Set N8N_PROXY_HOPS to 1 in your ENV, then restart your n8n instance.
DELETED the credential and recreate it (Modifying it don't work, you need to delete and recreate!)
Update your workflow
And it will works.