I am on an Intel based iMac Pro running Big Sur (11.6.1) I have followed every variant of the local playground setup I can find (all are some version of page 2 in this document https://docs.google.com/document/d/13112LHG9vVvNUs40oZSqZ-DF6_yFiT_SJZ2NaEmjMM4/edit#heading=h.orxckbtlhnnq) and while I can get both the playground client and server to start, and I can load up the playground client web page in my browser, I can't "compile" the code in the playground because of the web page receives 504 connection errors. So, here is what the playground web page looks like:
And I see these errors in the Plutus-playground-client console when I do anything in the UI:
[HPM] Error occurred while trying to proxy request /api/oauth/status from localhost:8009 to http://localhost:8080 (ECONNREFUSED) (https://nodejs.org/api/errors.html#errors_common_system_errors)
[HPM] Error occurred while trying to proxy request /api/contract from localhost:8009 to http://localhost:8080 (ECONNREFUSED) (https://nodejs.org/api/errors.html#errors_common_system_errors)
Interestingly enough, if I copy the "compile" request from the chrome inspector as a curl command and adjust the URL to be the playground-server port, The connection to the playground-server is successful and the code compiles, so something seems broken with the client.
Also, using lsof, I have verified that both the server and client are listening on the correct ports.