Hi Stefan,
While changing settings on the Nuki Bridge the Bridge is operating in a different mode and is not able to connect to the Smart Locks.
You need to finish configuration within the Nuki App by pressing the check icon in the upper right or leave Bridge settings screen with the back key.
Otherwise it will take 5 minutes of inactivity for the Bridge to leave this mode automatically.
You’ll notice it once it stops the constant blinking.
best,
Marc