This depends on the context to be fair. Front-end DoS can suddenly expand into botnet DDoS if you can trigger it by just serving a specific kind of URL. E.g. search goes into endless loop that makes requests into the backend.
It could still be a security error, but only if all availability errors are for that project. But after triage, the outcome is almost always “user can hang own browser on input which isn’t likely”. And yes, it’s a pity I wrote ‘almost’, which means having to check 99% false alarms.