I'm having trouble getting an IP address via DHCP on my HP ProLiant DL380 Gen9 server running Debian. I've tried various troubleshooting steps, but nothing seems to work.

Error messages:

• "No DHCPOFFERS received"
• "No working leases in persistent database - sleeping"
• "Activation of network connection failed" (GNOME)
• "IP configuration unavailable" (Plasma)

Hardware:

• HP ProLiant DL380 Gen9 server

Software:

• Debian operating system
• GNOME and Plasma desktop environments

Troubleshooting steps:

• Checked network cable and ensured it's properly connected
• Restarted network service
• Set /etc/NetworkManager/NetworkManager.conf managed=true

Additional information:

• Internet worked during the Debian installation process, but not after booting into the installed system.
• The problem occurs on both GNOME and Plasma desktop environments, but Plasma provides a slightly more helpful error message.

I'd appreciate any help or guidance on resolving this issue. Has anyone else experienced similar problems with DHCP on a HP ProLiant DL380 Gen9 server with Debian?