(Iphone) Cannot connect and have to reinstall after short period of inactivity/airplane mode and back

Good day to all.

A new user to nextdns and found it to be the service i actually require on iphone rather than vpn (filter out ads and maintain telco connection, no addition of ping/lag from using vpn be it minimal or moderate, access to websites that frowns on vpn).

However i have the issue of losing connection after short periods of inactivity, go to airplane mode and back (change of data mode and connection permanently loss). For the 12 hours i have used nextdns on iphone, i have reinstalled more than 10 times of the mobile configuration just to get it working again.

One time i waited for 30 secs after unlocking my phone, and its connection is back again, but it does not work all the time.

The main issue other than the connection loss, is the no connection during standby after short period of inactivity. With that i will not know if someone contacts me.

I am using free nextdns at the moment as i am in my first 12 hours of usage, hope to get any advise on the mentioned. Thanks!