I've followed this article in order to resize an attached volume's size.
https://www.digitalocean.com/docs/volumes/how-to/increase-size/
After resizing it on DigitalOcean, I figured out that my volume's partition is ext4. so according to the article, I've entered this command:

sudo resize2fs /dev/disk/by-id/scsi-0DO_Volume_volume-nyc3-02

The result is:

old_desc_blocks = 7, new_desc_blocks = 13
resize2fs: Permission denied to resize filesystem

What did I do wrong?

Thank you