Error in date format while submitting report

[akshayd1998]

wa_budat-low = '20210401'.
wa_budat-sign = 'I'.
wa_budat-option = 'BT'.
wa_budat-high = sy-datum.
APPEND wa_budat TO z_budat.
CLEAR wa_budat.
SUBMIT fagl_account_items_gl WITH sd_saknr IN z_wlsak
                               WITH so_wlbuk-low = '1000'
                               WITH x_opsel = ' '
                               WITH pa_stida = '08.09.2021'
                               WITH x_aisel = 'X'
                               WITH so_budat in z_budat
                               AND RETURN.

Please help im getting error in so_budat while executing Background.

ERROR:

Enter date in the format __.__.____

Message no. 00065

[Sandra_Rossi]

SO_BUDAT or PA_STIDA ?

If the issue is not about PA_STIDA, then how did you define SO_BUDAT ?