Hi @Donal_RC , Please check if the Spark History Server UI is TLS/SSL enabled or not. I suppose it is not, usually SHS WebUI is available only on http. (the log snippets suggest that it is plain http)

Chrome is automatically switching to https for some company domains, this feature is called HSTS - HTTP Strict Transport Security. Please check the addresss bar in Chrome, you should see that the URL starts with https.

If you have Internet Explorer, that doesn't do this, you can try there.

Alternatively you can:
- modify the URL and access the SHS with the host's IP address

- or enable TLS/SSL for the SHS too.

Hope this helps,

Miklos