Hi
it's not really a bug, but an omission in treatment of HTTP error codes that can happen during update search.
When the Internet connection is available through a proxy, you can specify winhttp proxy address by using the proxycfg.exe tool.
This produces a HTTP 407 error in paint.NET when we manually check for updates.
HTTP 407 (ProxyAuthenticationRequired)
It could be great, in that case, to display a login/password box and retry connection