The RUT (Russell 2000) index name is mentioned as supported in the docs:
We currently support the following indexes, in addition to tickers: VIX, MXACW, XWLD, MXUSA, MXEF, MXEA, DJI, RUI, RUT, OEX, OEX, SPX, XSP, XSP, SPESG, XND
-- https://help.usetrmnl.com/en/articles/10031211-stock-price
I also see it in the relevant code here.
But when I try to use RUT, I just see the SYMBOL_NOT_SUPPORTED error:
Also tried ^RUT (another common alias) for good measure but same result:
The complete list of stock tickers used is SPX, RUT, XAUUSD, XAGUSD. The SPX (S&P 500) index seems to work fine.