Hello quantumATKteam, I am experiencing a server connection issue in QuantumATK that occurs during execution and not at the submission stage. The job submits successfully and begins running, but during runtime it terminates with the error message “connection lost after 5 heartbeats”. The behavior is inconsistent: in some cases the calculation ran for about 12–15 days, in another case for around 10 days, and once it was cancelled within a single day, all failing with the same heartbeat connection error. This indicates that the server disconnects unpredictably while the simulation is actively executing. I have tried restarting QuantumATK and the system, reconnecting or re-adding the server in the Job Manager, and checking license and network status, but the issue persists. I would appreciate any suggestions regarding possible causes such as heartbeat timeout settings, long-runtime stability, network interruptions, license heartbeat limits, or resource constraints during extended QuantumATK calculations. Below I have pasted the lines printed on the log.
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Calculating Eigenvalues : [Sat Jan 3 10:16:40 2026]: Connection to server lost - reconnection attempt 2/5.
[Sat Jan 3 10:16:40 2026]: Connection to server lost - reconnection attempt 2/5.
============[Sat Jan 3 10:18:46 2026]: Connection to server lost - reconnection attempt 3/5.
[Sat Jan 3 10:18:46 2026]: Connection to server lost - reconnection attempt 3/5.
======[Sat Jan 3 10:20:46 2026]: Connection to server lost - reconnection attempt 4/5.
[Sat Jan 3 10:20:46 2026]: Connection to server lost - reconnection attempt 4/5.
=======[Sat Jan 3 10:22:46 2026]: Connection to server terminated after failing 5 heartbeats
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Calculating Eigenvalues : ===============================[Fri Jan 16 03:24:26 2026]: Connection to server terminated after failing 5 heartbeats
