Ok, the GS1900-24E is also running for me.
During the initial setup, the switch must be brought into the router's IP network, or the address must not be the same as the router. If I remember correctly, the switch has the default IP 192.168.1.1 and my FritzBox is 192.168.178.1. To get the switch into the router network, I assigned my PC a fixed IP (192.168.1.2) and connected only the PC to the switch via LAN. Then I accessed the web GUI and changed the IP to 192.168.178.2 and saved it. From that point on, access ended. Now everything is connected to the FB and you can access the switch via the IP from any device, including via WLAN. It is important that the range of fixed IPs is excluded from the DHCP range in the router.