Slickstream publishers may see browser or mobile friendly test errors in the Google Search Console that are generally described as WebSocket connection failures and are attributed to the slickstream.com domain. Examples are shown below. These failures are benign.
The browser or mobile friendly test are tests run by Google Search Console that emulate Google's search bot when it scans the page or site being tested. The idea being, that the test will highlight any problems that the actual search bot may see when crawling the page.
Google's real search bot disables WebSockets when indexing a page. So, when running the test, Google Search Console also disables WebSockets. If the test then detects that there were WebSockets in use, it warns you, in case you are relying on those WebSockets to deliver content that you may want to be indexed by the search bot.
Slickstream does indeed use WebSockets to deliver the content in the filmstrips and search results; however, that is not content you actually want Google to index on your page. So the use of WebSockets in this case is not actually limiting content you might want indexed, and these warnings are benign.
If you have questions about these specific errors/warnings or any other Google Search Console results related to Slickstream, please contact Slickstream directly at email@example.com.