Greetings,
The 3620 requires a 2.4Ghz broadcast for wireless connection. If your router is dual or triband and you are using SMART Connect or similar (One SSID for all broadcasts) the printer might have difficulty connecting.
What often helps is temporarily turning this off while performing set up.
Things to confirm:
Router
2.4 Ghz wireless is broadcasting
Can you connect another device succesfully
Verify passphrase of your wireless network
Use WPA2-PSK for security
I would suggest performing the set up steps again, wireless help:
Support | MG Series - Inkjet | PIXMA MG3620 | Canon USA
~Rick
Bay Area - CA
~R5 C (1.0.9.1), ~R50v (1.1.1) ~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
