Hi, if you factory reset the AP will go back to the PoE port for access - not the fiber. You need to then log back into the AP using the default 169.254.1.1 address and set up the radio via the PoE ethernet connection.
If you then want to use the fiber, make sure you review the Default (subscribers VLan) and the Management (access to AP radio) Vlan under the configuration VLAN settings and have them set differently on the AP radio. Set your AP IP address correctly under the Configuration IP settings and make sure the fiber going to the radio is ok and you have a correct SFP as per the details here - 3g 450m SMF SFP
Then lastly set the Ethernet Port Selection in General Configuration settings to SFP.
If the fiber then goes to a switch, set the VLANs correctly on the switch for access - and login to the AP.
Once you set the Ethernet port selection to SFP, you will not be able to access via the PoE ethernet connection, unless you once again factory reset the AP using the on/off/on/off etc reset method explained here - How to Enter Default Mode or Recovery Console for 450b, 450i and 450m series products