Unable submit forms

Hi,
We have 2 forms (contact form 7) in our web site. Recently, it is impossible to end the submits: with click on submit buttons, the page is frozen and nothing follows: particularly, for the form with payement via paypal, the paypal page never appear.
Perhaps if the fields are correct, messages are send and record in flamingo.
If the fields are not correct, not alert message is seen.
I try, localy, with an archived version date may 2020: it works correctly.
Here are all the versions off soft used in this 2 cases
Archive mai 2020 Site public
PHP 7.2.10 7.3.18
WordPress 5.4.1 5.5.1
TheFox theme 3.0.4 3.0.4
Askimet Anti-Spam 4.1.4 4.1.6
All-in-one-Migration 7.18 7.27
Contact Form 7 5.1.7 5.2.2
Contact Form 7 Paypal & Stripe Add-on 1.6.3 1.6.8
Enable JQuery Migrate Helper 1.0.1
Duplicate Post 3.2.4 3.2.5
Flamingo 2.1.1 2.2
LayerSlider WP 6.6.0 6.6.0
Loco Translate 2.3.1 2.4.3
Paypal IPN for WordPress 1.1.6 1.1.6
PDF Embedder 4.6 4.6
Really Simple SSL 3.3 3.3.5
Slider Revolution 5.4.6 5.4.6
TheFox Custom Post 3.0.0 3.0.0
W3 Total Cache 0.13.1 0.14.4
WP User avatar 2.2.5 2.2.7
Zeno Font Resizer 1.7.4 1.7.5
Editeur de page wpbakery 5.7 6.4.0
THank you very much in advance for your help
Sincerely yours
Jean-Louis

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