As per Section 107 of the CGST Act, 2017
Any person aggrieved by any decision or order passed under this Act or the State Goods and Services Tax Act or the Union Territory Goods and Services Tax Act by an adjudicating authority may appeal to such appellate authority as may be prescribed within three months from the date on which the said decision or order is communicated to such person.
Thus, in the instant case Appeal under Section 107 in the normal course of proceedings should be filed within 04.03.2021.
But the Hon'ble Supreme Court of India vide its Order dated 23.03.2020 directed that the periods of limitation, as prescribed under any general or special laws in respect of all judicial and quasi-judicial proceedings shall exclude the time period from 15.03.2020 to 14.03.2021. Consequently, the balance period of limitation remaining as on 15.03.2020, if any, shall become available with effect from 15.03.2021.
However, after the steep rise in COVID-19 cases, the Hon'ble Supreme Court of India on 27.04.2021 restored the order dated 23.03.2020 and in continuation of the order dated 08.03.2021 directed that the period(s) of limitation, as prescribed under any general or special laws in respect of all judicial or quasi-judicial proceedings, whether condonable or not, shall stand extended till further orders.
Thus referring to the above provisions you can file appeal against Impugned Order by citing SC Limitation Order due to COVID 19 Pandemic.
It may also be pertinent to note that CBDT vide it's Notification No. 24/2021 dated 01-06-2021 has also provided relaxation under section 168A of the CGST Act, 2017 and thus the time limit for completion of various actions, by any authority or by any person, under the GST Act, which falls during the period from 15th April, 2021 to 29th June, 2021, to be extended upto 30th June, 2021, subject to some exceptions. You can refer the notification here: https://taxninja.in/blog/highlights-of-recommendations-of-43rd-meeting-of-gst-council