Dear @Foppe,

- Omada SDN controller software installed on windows 7 machine acting as a server, IP address 192.168.1.172

- TL-SG2210p switch on IP 192.168.1.111 (Box says it's version 3, although I can only see V3.20 references online? Anyway, I flashed the latest V3.20 FW and it works, so I guess V3=V3.20

- 2x EAP245 V3, latest firmware, IP addresses 192.168.1.112 and 192.168.1.113 respectively

Let's ping the IP address of the EAP on the Win7 machine running the controller to check if any of the EAPs is accessible.

Also, try to disable the firewall on the Win7 machine for checking. Here is a detailed troubleshooting guide for your reference.

https://www.tp-link.com/support/faq/2581/

Dear @Foppe,

One more thing though: Multiple times a day, my cloud controller goes offline for a brief moment. I only notice because I receive a notification about this event. Any idea what could be the cause of that?

Do you mean that the controller shows offline from cloud access (https://omada.tplinkcloud.com/) but the Omada devices still work fine? For Omada SDN Software Controller, please ensure the Controller keeps running on the Internet, otherwise, the controller could show as offline from cloud access.