I have recently gone on all in with a TP- Link system for my property. 
The system so far:
Deco network:

3 XE75 Pro hardwired 

4 X50 hardwired 

Tapo

1 H500 hard wired

1 D210 wireless 

3 C530WS hardwired 

3 C610 wireless 2.4Ghz

2 DL100 wireless 
A bunch of smart switches, temperature monitors and water leak detection. 
Everything worked seamlessly until I lost internet connection with the D210. 
the H500 had previously gone offline, but came back after a day. 
When I try to reload the D210 it will not connect to the H500 and continues to say that it's a different network. I've tried connecting to my Mesh and my IoT, but it says the same message. 
My 3 C610 have connected perfectly using the IoT but the doorbell refuses. 
what am I doing wrong?