my guess is you probably have a sensor or limit safety switch fault.
when you have the unit running, activate the function and have someone look at the display and see what 'active' fault is showing.
you can look in fault history but it will probably have several faults listed in it.
what you want to pay attention to is the 'active' faults.
These will be showing on the display as long as they are present.
Also having a full serial number off the data tag inside the platform controls side cover will help get the right service information.
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