Claymore is closing itself (or crashing)?
23:45:55:363 10d4 XMR: Stratum - Connected (cryptonight.jp.nicehash.com:33355) (SSL/TLS)
23:45:55:645 10d4 got 79 bytes
23:45:55:645 10d4 buf: {"id":1,"jsonrpc":"2.0","error":{"code":-1,"message":"Internal server error"}}
23:45:55:645 10d4 parse packet: 76
23:45:55:645 10d4 Error in server response
: {"id":1,"jsonrpc":"2.0","error":{"code":-1,"message":"Internalservererror"}}
23:45:55:645 10d4 buf was cleared
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After that, the miners is closed. The error handler should try reconnect infinitely after x seconds instead.