UPDATE: last week Bing suddenly starting indexing ledburypoetry.org.uk even though I had given up trying to make any further changes to the site to appease it. Consequently it's on Ecosia, etc as well. Still wish I knew what they had against us in the first place.

@Tomalaweb - I have done all of those things and repeatedly use the Bing Webmaster tools to check for errors, etc (I grudgingly admit they are useful), but all attempts to have the domain listed in Bing fail. If I Google 'poetry festival' we come first after the sponsored entries, in Bing not a mention even by page 5. It's so frustrating!!! I would say that our efforts to get Bing to show us have been rewarded by some improvements in our Google ranking though.

Experiencing the same problem with ledburypoetry.org.uk. Page 1 listing on Google, nothing in Bing (or SEs that depend on Bing such as Ecosia). Webmaster tools tell me the URL is known but cannot appear because it 'has issues which are preventing indexation.' Have followed their guidelines as far as possible

Scans come back with 0 errors and just a warning about 'HTML size is too long' but I think that's a Bing error as it's a page with a form on and others have commented on this anomaly elsewhere.

If I submit the URL to Webmaster tools URL Inspection it tells me it's OK and I then submit for inclusion but never have any success it getting the site to appear. Done this several times since September.

I advise everyone I know not to rely on Bing to find what they are looking for as clearly other sites are not listed but my tree-hugging colleague insists on only using Ecosia to search in order to plant more trees so it would be an achievement to get listed again.

Totally frustrated by Bing and wish everyone would stop using it. It is really annoying that on new Windows installs you have to work quite hard to not have Edge and Bing as the default search.

Just to add another dissatisfied user here - we have a website (ledburypoetry.org.uk) which, as far as I can tell, does not violate the Bing guidelines and preforms well in Google but I was mystified when a friend said she could not find it at all. I noted she was using Edge/Bing (yuk!) and even the exact URL produced no results. So we tried Google and found it at once at the top of page 1. I created a Bing webmaster account and likewise discovered that the URL was delisted in Bing because it "didn't conform to their guidelines" (no further explanation). I don't object to sites being downgraded for poor design etc, but they shouldn't be blocked altogether! My requests to relist it have gone nowhere.