Originally Posted by guest4711
So it looks like your /data/adb/magisk.db is broken (our your Magisk Manager is not in sync with your Magisk). In this database all settings for Magisk Hide and Magisk SU are stored.
To check it, boot into TWRP, use internal filemanager to move this db out of the way (rename it to magisk.db.save e.g.) and reboot. Then try again.
If it does not solve your problem, you may boot into TWRP again and put your saved database back into place...
i gave this a try, other apps request root, adaway does not. but thanks for the tip
Update: thx to post of guest4711 i was finally able to solve the issue.
i edited the magisk.db file manually with sqlite and added under policies table a line:
then symbolic linked magisk su to system/xbin
ln -s /sbin/su /system/xbin/su
rebooted and adaway is working again.