Sending fails if no file is attached

Do you get any response message after you submit the form?

Yes, we get the yellow validation error. And for every upload field where no file was selected, a message appears saying that the upload failed.

We have five fields for file uploads, but these are all optional. If I select all five files it works.

I looked at the JSON response. The following error appears for every file upload field where no file has been selected (“file-914” is the field id in this example):

error_id: "wpcf7-f1102-p2754-o1-ve-file-914"

See Editing form template

What content do you have in the Form tab panel?

<p>Versicherungsnummer<br />
[text* Versicherungsnummer]</p>

<p>Versicherer<br />
[text* Versicherer]</p>

<p><b>Versicherungsnehmer/in:</b></p>

<p>Vorname/ Nachname<br />
 [text* your-name] </p>

<p>Stra?e/ Hausnummer<br />
[text* Strasse]</p>

<p>Postleitzahl/ Ort<br />
[text* Ort]</p>

<p>Ihre E-Mail-Adresse <br />
    [email* your-email] </p>

<p>Telefon tagsüber<br />
[tel* Telefon]</p>

<p>Bankverbindung (IBAN)<br />
[text iban]</p>

<p>Kreditinstitut<br />
[text kredit]</p>

Sind Sie vorsteuerabzugsberechtigt?<br />
[radio Vorsteuer "Ja" "Nein"]

<p><b>Was ist passiert</b></p>

<p>Datum des Schadens<br />
[text* datum]</p>

<p>Schadenort<br />
[text schort]</p>

<p>Sachverhalt/ Hergang<br />
    [textarea your-hergang] </p>

<p>Wie hoch wird der Schaden gesch?tzt ?<br />
[text schhoehe]</p>

<p>sonstige Anmerkungen<br />
    [textarea your-message] </p>

<p><b>Wurde der Schaden polizeilich aufgenommen?</b></p><br />
[radio polauf "Ja" "Nein"]

<p>Polizeidienststelle:<br />
[text polstell]</p>

<p>Tagebuch-Nr:<br />
[text tagebuchhoehe]</p>

<p>Datei(en) anh?ngen (jeweils max. 5 MB)<br />
[file file-914 limit:5mb]
[file file-915 limit:5mb]
[file file-916 limit:5mb]
[file file-917 limit:5mb]
[file file-918 limit:5mb]</p>

[acceptance checkbox-dschutz] <a target="new" >Ich habe die Datenschutzerkl?rung gelesen</a>[/acceptance]
[acceptance checkbox-datainfo] <a >Ich habe die Information und Einwilligung zur Datenverarbeitung der von mir übermittelten Nachricht gelesen und erkl?re mich hiermit einverstanden.</a> [/acceptance]

<p>[submit "Senden"]</p>

What other plugins and theme do you use on the site?

The theme is called Bridge:
https://themeforest.net/item/bridge-creative-multipurpose-wordpress-theme/7315054

Plugins:

• Advanced Editor Tools
• Buttonizer – Smart Floating Action Button
• Classic Editor
• Contact Form 7
• Cookie Notice & Compliance for GDPR / CCPA
• Duplicate Page
• Envato Market
• Nav Menu Collapse
• Nested Pages
• ShortPixel Image Optimizer
• Simple Custom CSS and JS
• Slider Revolution
• UberMenu 3 – The Ultimate WordPress Mega Menu
• UpdraftPlus – Backup/Restore
• WP Extra File Types
• WP Fastest Cache
• WP Glossary – Encyclopedia / Lexicon / Knowledge Base / Wiki / Dictionary
• WP Hide & Security Enhancer
• WP Mail SMTP
• WP Meta and Date remover
• WP Post Modules
• WP STAGING WordPress Backup Plugin – Backup Duplicator & Migration
• WPBakery Page Builder
• Yoast SEO

Try switching to the default theme, deactivating all plugins excluding Contact Form 7, Classic Editor, WP Mail SMTP and Yoast SEO, and clearing all cache data.

Why you are advised to deactivate plugins and switch to the default theme.

Thank you! After I disabled all plugins the form worked. Then I gradually reactivated individual plugins and tested the functionality of the form. Finally, I now have all plugins active again, except for “WP Hide & Security Enhancer”. So this is obviously responsible for the problems.

Unfortunately, I don’t really know this plugin or its function. I didn’t create this website myself, I just took over its maintenance. Do you know this plugin?

I will leave this plugin disabled for now. But it is probably valuable information for you that there appears to be a compatibility problem between this and your plugin.