Troubleshooting Random Disconnections

Hello I have a Routerboard 750 with OS 4.9 this router was being used to manage redundancy from ADSL and Satellite connections to our network. I changed ISP and now I only have a satellite connection using Ether1 as Gateway (default config), Ether2 for “local” network and Ether5 for Guest Network. I have isolated Ether5 with firewall and limited bandwith (that works great).

My problem is during the day all “local network” computers lose connectiong for a couple of seconds and then everything goes back to normal. At first I thought it was the ISP because I connected to Winbox and saw the Gateway Rx at 0 and Tx with activity. But last time I was already on Winbox and when the connection was lost I lost connection to Winbox too and I also couldn’t access the shared folders so that means it wasn’t just connection with the gateway but with the whole network. What could be failing? I’m using DHCP from the Routerboard but have my Windows Server as main DNS Server.

I’m new to forums so guide me if I’m doing something wrong.

I removed my Windows Server IP as main DNS server since I’m handling local domain DNS request with Mangle and Layer 7 Protocols rules. That seems to have fixed my issues with network connectivity loss. But I’m definatedly losing connecting with the ISP randomly. Think this has anything to do with the MikroTik or is it definatedly the ISP?