Greetings ,
I recommend you choose one interface and stick with that. If you're only going to use the printer with one system, USB is fine. If you intend to use it with other network devices, use wireless. This will allow any device connecting to that Network to print.
To reset the network information, SSID, password and IP if one was assigned, re-run the product setup. You can download this from the printers support portal.
https://www.csai.canon.com/support/p/pixma-mg3620
~Rick
Bay Area - CA
~R5 C (1.0.9.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, ~RF 200-800 +RF 1.4x TC, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve Studio ~ImageClass MF644Cdw/MF656Cdw ~Pixel 8 ~CarePaks Are Worth It
