After any major firmware update, residual old settings can cause conflicts.
First, determine if you actually need an update. Denon Avr E300 Firmware Update
Denon AVR E300 firmware update, Denon AVR-E300 update error, USB firmware update Denon, E300 brick fix, Denon legacy firmware 6940. After any major firmware update, residual old settings
: Turn on your receiver and ensure it has an active internet connection. After any major firmware update