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M
What is the output of ip l sh
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M
Is there a typo in the address or gateway? Your gateway is not in your network
What is the address of your PC (Windows ipconfig Linux ip -br a s)
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M
Have you read the docs?
https://pve.proxmox.com/wiki/Upgrade_from_8_to_9#Actions_step-by-step
Try to connect via console or ssh
