Failed to connect to dhcp

Hello all,
I’m using openHABian on a rpi3 and I had all my systems shutdown for the last year.
In the mean time I changed my router with a tp link ax10 and I’m trying to start my system but I get this message when rpi load that say Failed to connect with dhcp on all interfaces!
What I did: I setup up ip and gateway in /network/interfaces
I setup the WiFi on the dhcp.conf file to my wireless network.
I setup the WiFi network on openhabian-config.
I did port forward on my router according to rpi ip.
I can’t access it with putty and it doesn’t respond to ping.
I need to say that before it worked ok with rpi WiFi
Do I have to reinstall openHABian on my rpi?
Could anyone please help?
Thanks for the answer and apologize if I missed a topic related to this one.

So is the issue that your RPI won’t connect to your router?

Are you connecting to a 2.4g network or mixed?

Can you plug a network cable in to change setting?

Thanks for the answer! I made some tests this evening through lan and it’s working intra network so there are 2 issues: the WiFi connection doesn’t work anymore and there is something wrong in the port forward section couse I can’t access the app outside the WiFi connection.

Ok the way I understand it is after initial config of the wifi it saves the data in another location and you can edit it there.

In ssh to pi

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

Edit save unplug network and reboot.