not publishing (error uploading photos)

hello, i just purchased the instamatic but it is not working on my wordpress. I constantly get this message: [5-Feb-2020 16:15:19 UTC] Failed to upload image to Instagram: /var/www/vhosts/onlarissa.gr/httpdocs/wp-content/uploads/2020/02/2815082.jpg, error:   Please fix it or refund me. Thank's