Thank you Art,
I have found out what the problem is: I'm using "inch" system and MachCload expect "mm" coordinates.
I have brought my cloud file in Excel and multiplied each values by 25.4 and saved it.
When opened in MachCloud now it can meshed and my parts are recognizable

Please when you have a minute to work on MachCloud a mm/inch option would be very usefull

Great to see significant results.
Gaston