error in pre-PCR

This is likely from the heated lid not getting to temperature before starting the run, on these older units they can be a bit slow and if you have the lid lifted up or pressed against a plate it really does struggle, my suggestion would be to perhaps lower the lid set temperature or help it get up to temperature by keeping it closed and not pressed against anything.

Thank you for your response. The issue doesn't appear to be with the lid, as it consistently heats to 103°C before the run, as expected. However, once the run begins, the sample temperature does not exceed 30°C. When we attempted a calibration verification, the lid temperature reached 85°C, but the block temperature remained at 28-30°C.