Copy Original Estimate

[Todd Winton]

I am trying to copy original estimate into another field and am getting Transition Failed, Internal Server Error and the transition does not occur.  

I have tried this with both a text and a number field.

Is there something I am doing wrong or is there something with the original estimate field that doesn't allow this?

[Munnir Abdulhamid]

sometimes is custom field restrictions If the original estimate is a custom field, there might be restrictions on copying its value. Check the custom field configuration to see if it allows copying its value to other fields.

Or 

Field Type Compatibility: Ensure the destination field is compatible with the data type of the original estimate. If the original estimate is a numeric value, make sure the destination field is also a numeric field. If it's a text value, ensure the destination field is a text field.