src/vs/workbench/contrib/extensions/browser/extensionsViewlet.ts/ExtensionsViewPaneContainer/onError
class ExtensionsViewPaneContainer:	private onError(err: Error): void {
		if (isCancellationError(err)) {
			return;
		}

		const message = err && err.message || '';

		if (/ECONNREFUSED/.test(message)) {
			const error = createErrorWithActions(localize('suggestProxyError', "Marketplace returned 'ECONNREFUSED'. Please check the 'http.proxy' setting."), [
				new Action('open user settings', localize('open user settings', "Open User Settings"), undefined, true, () => this.preferencesService.openUserSettings())
			]);

			this.notificationService.error(error);
			return;
		}

		this.notificationService.error(err);
	}