Hi @DAVITz ,
One of the fields is populated with a date/time (field_9), and field_1 (which I'm assuming that is equivalent to "fecha" Excel column) seems to have a Serial date. I've just tested in Excel, and the serial date from field_1 (38718) is equivalent to 2006-01-01 (same of field_9). Is this the expected date for field_1? Also, just to confirm: is there any other of these fields expected to be a date? If yes, which one?
I also ran some tests in Power Automate to convert it from Serial to ISO date. First, I assigned the 38718 to a "Compose" action (you don't need to do it from your end, as you already have this value extracted from Excel):

Then, in the "Create item" action, I included an expression very similar to the proposed in this topic solution:

Expression: addDays('1899-12-30', outputs('Compose'), 'dd-MM-yyyy'). Make sure to replace the red text for the dynamic content of "fecha".
After running the flow, this is the output:

Let me know if it works!!