Too many sub-requests for CRON Job

Why i’m facing this error, even when my requests are lower than 1000.

My Workers plan Standard and Paid.

	async scheduled(event, env, ctx) {	
		const tg_bot_token = "xxx"
		const db_table_name = "sent_files"
		const admin = [xxx]
		ctx.waitUntil(DeleteFilesToBeDeleted());
		async function DeleteFilesToBeDeleted() {
			const currentTime = Date.now();
			const query = `SELECT file_id, user_id FROM ${db_table_name} WHERE ${currentTime} > max_time`;
			try {
				const { results } = await env.DB.prepare(query).all();
				const totalResults = results.length;
				if (totalResults > 0) {
					for (var i = 0; i < 400; i++) {
						var file_id = results[i].file_id
						var user_id = results[i].user_id
						var res = await fetch("https://api.telegram.org/bot" + tg_bot_token + "/deleteMessage?disable_web_page_preview=true&chat_id=" + user_id + "&message_id=" + file_id, {
							method: "GET",
						});
                        var text = await res.text()
                        console.log(text)
						const newquery = `DELETE FROM ${db_table_name} WHERE file_id = '${file_id}';`;
						await env.DB.prepare(newquery).all();		
					}
				}
			} catch (e) {
				// send log to admin
                console.log(e)
				await fetch("https://api.telegram.org/bot" + tg_bot_token + "/SendMessage?disable_web_page_preview=true&chat_id=" + admin[0] + "&text=Error in DeleteFilesToBeDeleted Function.\n\n" + encodeURIComponent(e), {
					method: "GET",
				});
			}
		}
		return new Response("OK", {
			status: 200,
			headers: {
				'content-type': 'application/json',
			},
		});
	}