I have been trying unsuccessfully to post the result of an RSS feed from Mastodon to Twitter.
Twitter node posts static text, but currently not the result of an expression from an earlier node.
It seems to be a bug introduced in the latest version of n8n 0.139.1. Please downgrade to 0.138 or set the env variable N8N_USE_DEPRECATED_REQUEST_LIB=true
Posted FYI if you are struggling with similar.