Error 404

Hello,
the plugin does not work properly on the site.
If you send a message, there is a loading animation that doesn’t stop. the message arrives but very often (five – six times). The console shows me an error 404.

Console Error:

autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402 POST https://fahrschule-schomaker.de/kontakt/contact-form-7/v1/contact-forms/12/feedback?_locale=user 404
F @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
tryCatch @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:262
invoke @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:262
t.<computed> @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:262
n @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
a @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
I @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
f @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
I @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
X @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:402
f @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403
autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403 {code: "invalid_json", message: "The response is not a valid JSON response."}
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403
Promise.catch (async)
f @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403
(anonymous) @ autoptimize_e9e04cdb55a53c684bbb88c15aa934ae.js:403

The page I need help with: [log in to see the link]