Got a new router from the ISP and my ESP8266 NodeMCUs are causing problems, they need very long to connect to WiFi (3-4 mins), which wouldn't be that big of a problem, but they also don't connect to the MQTT Broker (I am running OpenHAB2 on a Raspberry Pi(Ethernet) and MQTT Broker). "Attempting to connect to MQTT Server..." is printed forever.
OpenHAB and Raspberry are working fine, I can send/recieve MQTT messages and can also send/recieve messages to OpenHAB from my notebook with the MQTT.fx client.
Since I didn't change anything in the ESP8266 code (mostly Arduino FastLED code) and it worked fine with the old router, I assume the code is OK and the solution needs to be somewhat with the new Router?
Anyone any idea what I could try? The router is a noname product (the ISP just prints his logo on it) like the old one was, the router setup page is nearly same like the old one, both provide DHCP settings.
I tried to give the ESP a reserved IP but it didn't help.
Thanks in advance.