Hi Matthias,

Thank you for reaching out.

Based on your description, this does not appear to be a known issue with SP Page Builder. Since the form is working sometimes but not always, it is usually related to the mail server or delivery configuration, not the form itself.

We would recommend checking the following: • Verify your Joomla Global Configuration → Mail Settings (SMTP is recommended instead of PHP Mail). • Check with your hosting provider if there are any email sending limits, restrictions, or temporary blocks. • Ensure emails are not being marked as spam or filtered. • If “From” and “To” are the same, try using a different From email (some servers reject this). • Review server/email logs to see if any requests are being blocked or failing.

Please let us know if you need further assistance.

Best regards,