sliver server complete restore - failing client connections

Hello, we have lost our current /root/.sliver folder and in use sliver server binary (we dont know in which version it was, logs say 1.5.39) . We have a 2 month old backup copy of whole .sliver folder. Restoring from the backup folder into "new" .sliver folder works, the sliver server lists old implants and beacons. However, the server is not accepting clients connection with error - remote error tls: bad certificate. We have tried backup .sliver folder with the versions 1.66, 1.7 and 1.5.4.

Do we have to tweak any config maybe? Any help is appreciated. Thank you.

The error from sliver.log with version

INFO[2026-06-12T21:08:02Z] [sliver/server/c2/mtls.go:85] Accepted incoming connection: X.X.X.X:45811 ERRO[2026-06-12T21:08:02Z] [sliver/server/c2/mtls.go:165] Socket error (read msg-length): remote error: tls: bad certificate ERRO[2026-06-12T21:08:02Z] [sliver/server/c2/mtls.go:103] Socket read error remote error: tls: bad certificate INFO[2026-06-12T21:08:05Z] [sliver/server/c2/mtls.go:85] Accepted incoming connection: X.X.X.X:45916 ERRO[2026-06-12T21:08:05Z] [sliver/server/c2/mtls.go:165] Socket error (read msg-length): remote error: tls: bad certificate ERRO[2026-06-12T21:08:05Z] [sliver/server/c2/mtls.go:103] Socket read error remote error: tls: bad certificate