NextDNS causes huge delays at start

I had been using nextdns for a few months on my several devices. It was excellent. But since recently it causes my devices to prevent connecting to the internet in web browsers (both safari and chrome) and youtube. There was no problem with Telegram. It would take more than a minute like that and then it works. After that I can work normally. But when the phone is locked (not in use), and when I visit a website, again the same problem happens. When I switch to a different dns, this does not happen. Therefore I know for sure nexdns is the culprit.