Sudden network issues with a NASNetwork, Troubleshooting

I have a Synology NAS hooked up t my Netgear router.

It has worked flawlessly up to now.

I can access the nas via http://192.168.1.8:5000/index.cgi

I can access any of the shares. The IP adress for NAS is reserved.

I cant ping it, i cant even ping any machines on my network,

I have 7-8 devices, most with windows 10.

The other day the firewall on main computer started to act. I constant have to approve apps or services.

Cant access the NAS from any computer, wired or wif, only via browser and port 5000.

Has to be a setting on router that prevents me from accessing the NAS. But what setting?