Dhcpcd.service failed

The initial difficulties due to some misunderstandings have been overcome. But after I unlocked the SSH access for all services, the dhcpcd.service crashed. The message in the log is: failed to start dhcpcd.service on all interfaces.
By the way, I didn’t manage to activate WiFi. I am not sure how to enter the information. If the entries are case senisitive

I can’t help much with the rest but the entries are definitely case sensitive.

For those who may be able to help, there is far too little information here to provide that help. What OS? How did you install? What version? What instructions are you following?