Error message

Resolve a 101 error preventing a second email from sending in CF after a Joomla upgrade.

Overview

The issue is caused by a specific reply-to email address triggering a restriction in the email server's processing library.
Remove or change the problematic reply-to email address in the second email action's settings to avoid the server restriction.

Answered
ChronoForms v8
kr kraadde 06 Feb, 2026

Max,

after upgrading from Joomla 5.4.2 to version 6,0.2  I got the following error message. Can you propose any solution?:

The form submit does work far as as the data are stored cortrectly into the table and the first email is sent correctly to the given address, however not to the second email. Email checked and it is OK and also tried to remove the underline from the address but with no success..Does joomla 6 not allow multiple email sending??

Max_admin Max_admin 07 Feb, 2026

Hi kraadde

You have some email library or plugin which does some email processing before the email is sent, this library fails at some point:

Error message  image 1

You need to find why it fails or disable it, the image you posted does not show the error message

Max, ChronoForms developer
ChronoMyAdmin: Database administration within Joomla, no phpMyAdmin needed.
ChronoMails simplifies Joomla email: newsletters, logging, and custom templates.
kr kraadde 07 Feb, 2026

Max, strange, but the first email is sent correctly and when i siable the second email the first is sent and no erroe message anymor!

Max_admin Max_admin 07 Feb, 2026

so it's some setting in the 2nd email which triggers the problem, what is the error message ?

Max, ChronoForms developer
ChronoMyAdmin: Database administration within Joomla, no phpMyAdmin needed.
ChronoMails simplifies Joomla email: newsletters, logging, and custom templates.
kr kraadde 07 Feb, 2026

But the librery is part of the Joomla core. See below. google say:

Yes, the{Link: algo26-matthias/idna-convert https://github.com/joomla/joomla-cms/issues/46688}library is part of the core dependencies in Joomla 6, often located inlibraries/vendor/algo26-matthias/idna-convert. It is used for handling internationalized domain names and was updated to version 4.2+ to improve PHP 8.5 compatibility and email-to-punycode conversion in the CMS.Key Details Regarding Joomla 6 and idna-convert:

If you are seeing errors related toalgo26-matthias/idna-convertin Joomla 6, ensure your CMS is updated to the latest version to include the necessary library updates.

The settings of both emais are equal, besides the address.

Max_admin Max_admin 08 Feb, 2026

Ok, what is the error message ?

And please try to switch the order of the 2 emails, does the first email still get sent or not ?

Max, ChronoForms developer
ChronoMyAdmin: Database administration within Joomla, no phpMyAdmin needed.
ChronoMails simplifies Joomla email: newsletters, logging, and custom templates.
kr kraadde 08 Feb, 2026
Answer
1 Likes

Max,

Maybe I found the solution. The first Email  (email76) was always working perfectly 

The settings of the (email77) included in the entry in the reply email : {data:email}.

I removed the entry in the reply email and suddently everything works, both email are sent and no more 101 error

Is that a possible bug?

Error message  image 2

And that was the error message:

Die angeforderte Seite konnte nicht gefunden werden.

Während der Anfrage ist ein Fehler aufgetreten.

Die Seite kann nicht angezeigt werden, weil:

  • einveraltetes Lesezeichenaufgerufen wurde.
  • einefalsche Adresseaufgerufen wurde.
  • über eine Suchmaschine einveralteter Index dieser Websiteaufgerufen wurde.
  • keine Zugriffsrechtefür diese Seite vorhanden sind.

Zur Startseite wechseln

Bei Problemen ist der Administrator dieser Website zuständig.

101Prohibited input U+00000020

Max_admin Max_admin 08 Feb, 2026

No, this is not a bug, if your Email server (SMTP or PHP) has specific Reply Email restrictions then this will happen, that's why it is recommended to test the email with minimal settings first.

Max, ChronoForms developer
ChronoMyAdmin: Database administration within Joomla, no phpMyAdmin needed.
ChronoMails simplifies Joomla email: newsletters, logging, and custom templates.
kr kraadde 08 Feb, 2026

Are you mentionning the 

  • SPF (Sender Policy Framework)which is activated on my email server? But this is the case since the webpage was creaded and never was a problem ..

Regards

Adriano

Max_admin Max_admin 09 Feb, 2026

Hi Adriano

You can try a different Reply Email, or a Reply Email @the same domain, usually this depends on the mailing server settings, do you have other email actions with Reply Email which are working fine ?

Max, ChronoForms developer
ChronoMyAdmin: Database administration within Joomla, no phpMyAdmin needed.
ChronoMails simplifies Joomla email: newsletters, logging, and custom templates.
Post a Reply