Why did the requests stop?

{
    "caseSensitive": false,
    "keywords": [
        "Oberoi"
    ],
    "linkSelector": "a[href]",
    "maxConcurrency": 50,
    "maxDepth": 5,
    "maxPagesPerCrawl": 100,
    "proxyConfiguration": {
        "useApifyProxy": true
    },
    "retireInstanceAfterRequestCount": 50,
    "scanScripts": false,
    "startUrls": [
        {
            "url": "http://dopline.ru/"
        },
        {
            "url": "http://plantravel.ru"
        },
        {
            "url": "https://www.oberoihotels.com/"
        },
        {
            "url": "https://www.sodis.ru/"
        }
    ],
    "useBrowser": false,
    "useChrome": false
}