The string 'MMMM/dd/yyyy' was not recognized as a valid DateTime. There is an unknown word starting at index '0'

Hello @kmilo_de_los_santos
Try this

DateTime.ParseExact("ENE/15/2022","MMM/dd/yyyy",System.Globalization.CultureInfo.GetCultureInfo("es-ES")).ToString("MMM-dd-yyyy")

DateTime.ParseExact("ENE/15/2022","MMM/dd/yyyy",System.Globalization.CultureInfo.GetCultureInfo("es-ES")).ToString("MMMM-dd-yyyy")

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