After every restart, I have to re-enter the passkey for the WLAN. It is not saved even though “Remember me” is clicked.
Hi @Morphy66 never experienced that in the last 2 months for once …
What I experienced sometimes is that the network is not visible yet still connected .
Try to save the WiFi password , and when connected just shut down the WiFi before you restart and see if that worked for you.
If not please write to customer@revopoint3d.com for assistance with the hardware/ software issue
Do you have a lot of special characters in the password or is it all alphanumeric?
I did experience some wierd WiFi behaviour with my Miraco a few months ago at work on an access point that had a very complex password.
It is all alphanumeric! 
Unfortunately, this does not solve the problem.
The SSID is visible.
I will now reset the device - maybe that will help!
A factory reset did nothing. 
The Wi-Fi does not connect automatically and I have to enter the password again when reconnecting.
You should not reset the device … please remember that a reset will also remove any custom calibration files , it is a factory reset that only removes your personal settings and scans, not fixing your system software .
Please write to customer@revopoint3d.com
Now you will have to wait until Monday for assistance. As there is nothing else we can help you here in the forum this weekend, you need a technical appointment and eventual system update to fix that issue with the reboot glitch .
I have solved the problem. 
It was because the combination of PiHole & Unbound caused the scanner not to save the WLAN connection.
After I excluded the scanner, it worked without any problems! 
Ah! Thank you for letting me know … just in case we get another case … good to know !
I would never actually guess that …