The "failed to retrieve server list" error in Blue Protocol Star Resonance may be due to the game being region-locked, meaning your country might not be included in the list of release regions. This issue arises even during the game's "global" launch, as several countries were excluded. Using a VPN can help bypass this restriction by masking your IP address to appear as if you are connecting from a supported location. If you are in a supported region but still encounter the error, check if you are connected to a VPN, as it may be causing the problem.