We’ve take a look your contact form but it seems something going wrong and we didn’t find any problem source. But our demo working properly with contact form 7 https://themeofwp.com/architecto/contact-us/ we tested a several times your contact form but no luck.
Wer suggest to you please deactivate some plugins and test again;
* Cookie Law Info
* Add Publicize Support for Works
* EWWW Image Optimizer and others.