Others may add more details about this, but I noticed a reference to en-gb.wikipedia.org which may be caused by (a) the use of British English as the UI language, and (b) the assumption that all UI languages have a Wikipedia. In this case the corresponding Wikipedia for British English (en-gb) is English Wikipedia.

It may be worth investigating how many of the issues are related to this, and how many occur also for languages where a Wikipedia does exist.

In T273744#6799824, @Pginer-WMF wrote:

Others may add more details about this, but I noticed a reference to en-gb.wikipedia.org which may be caused by (a) the use of British English as the UI language, and (b) the assumption that all UI languages have a Wikipedia. In this case the corresponding Wikipedia for British English (en-gb) is English Wikipedia.

It may be worth investigating how many of the issues are related to this, and how many occur also for languages where a Wikipedia does exist.

if I change the UI language to english (not gb) I get this

About en-gb requests: there is a related patch that will be deployed to test server very soon

about the second request error: recommendation rest api seems to be down, not sure why. However, this request is needed only for page article suggestions, which is something that won't be supported at this point. https://gerrit.wikimedia.org/r/c/mediawiki/extensions/ContentTranslation/+/657564 is taking care of it, and requests to fetch page suggestions won't be sent after it is merged.