Double sending necessary

Hello,
I have this problem: If one fills the form but forgetting a required field, the error message appears – so far so correct. But after filling the field the form is not submitted by the first pushing of the “Send” button. You have to push it again to submit the message. This is annoying, perhaps some users might not recognize that and leave the page without pushing the button for the second time!
(Checked on Firefox and Chrome, I shut off WP Rocket and all the plugins that have to do with CF7 (Honeypot, CF7Skins etc.). The problem remains. Latest version of WP and CF7, all plugins updated.)
Thanks for help!

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