Comment on Stallion WordPress SEO Theme by SEO Dave.
WordPress Error Message – Are you sure you want to do this? Please try again
And you’ll see there’s a lot of causes of this error, had one other customer with this issue: https://stallion-theme.co.uk/wordpress-theme-update-tutorial/?cid=17554
Looks like it was a max upload file size issue (many hosts have max upload size at around 2MB, Stallion needs around 10MB) which would normally give a different error. Might be another cause for you, for a quick fix try installing using FTP.