sophos xg125 problem with fiber

Job ID: 35258225

Budget: €8 – €30 EUR

We have a sophos firewall 125 we remove the cable from lan1 and added fiber optic from port 9 to the fiber switch.
no internet or dhcp is giving. when we add the lan 1 to the switch is working. so basically is working with lan cables to switch only and not fiber to fiber swich. we need someone to just. maybe is transeiver we dont know maybe is not companible. but we wee the lights blinking and give us a speed link