I'm running Chrome Version 119.0.6045.214 (Official Build) (64-bit) on a very underpowered Chromebook (n3060, 4MB, 32GB).
All of my downloads failed (even gradually reducing number of days) until I went to chrome://serviceworker-internals/ and manually started the Windy service worker. After that all of them worked.
There's a message in the service worker logs but I'm not sure it's related:
Console: {"lineNumber":0,"message":"Access to fetch at 'https://ims-s.windy.com/account/images/1599902-profileavatar.png?1688824588440' from origin 'https://www.windy.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.","message_level":3,"sourceIdentifier":1,"sourceURL":""}