Ion date component problem with the offset zone time

I get the date value from the API and put it to the ion date component.
I receive the data in this format:
1970-01-01T17: 21: 00 + 00: 00
I put the data to
<ion-datetime displayFormat =" HH: mm "formControlName =" startHour "> </ ion-datetime>
That I have
18:21 and no 17:21
How can I solve this problem?