Fatal Error: Call to undefined function idna_maps_not_std3

[Darkness7148]

Just been greeted with this fatal error on my forum on every page.

Fatal error: Uncaught Error: Call to undefined function idna_maps_not_std3()

You cannot view this attachment.

I've had to comment out the call to the function in Class-Punycode.php, Lines 536/537.

SMF 2.1.6.

[Doug Heffernan]

Just been greeted with this fatal error on my forum on every page.

What was the latest change done to the forum prior to this happening?

[Darkness7148]

Nothing at all. Just came out of the blue.

As I said, I upgraded to SMF 2.1.5 and then 2.1.6 when you released them this week.

[Kindred]

Do you run a maps mod?

[Aleksi "Lex" Kilpinen]

Seems like standard code, but I'll be damned if I knew where to look at next to find out why it does that
https://github.com/SimpleMachines/SMF/blob/release-2.1/Sources/Class-Punycode.php#L537

@Sesquipedalian Got a hint for us?

[@rjen]

The same happened to me: after the upgrade to 2.1.6 complete forum went down http 500.

Directy after the upgrade the forum was up and running. I have has posts after the the upgrade: last post was two hours after I successfully posted that the forum was upgraded...

Same errors, I have commented out the two lines as well, and it is now back.
Something definately not correct here..

PHP Version 8.2.28
SMF Version 2.1.6
Themes: Curve and One Curve copy

FYI: I have a test forum running in same setup in a subdomain: I tested the upgrade there and it works fine. The main forum went down...

MODS:
1    Stupid bouncy BBC    2.1.9   
2    Downloads System    3.0.14   
3    Automatic Attachment Rotation (and Resize)    6.26
4    AJAX Recent Topics for SMF2.1
5    Sticky Topics Order FJR    0.6
6    Simple Audio Video Embedder    7.0.3a
7    AutoPurge old Topics
8    Spiders Don't Increase Topic Views
9    Remove "Last Edit"
10    Users Online Today    2.1.2
11    Quick Reply Attachments Button    1.0
13    AutoLock Old Topics for SMF2.1
14    Board Sorting Method    1.0.1
15    Real Popup with AdBlock Detection    1.8
16    EU Cookie SMF2.1    2.1
17    Forum Width Setting    1.2
18    SMF 2.1.5 Update    1.0
19    SMF 2.1.4 Update    1.0
20    Mod Version Checker    1.1
21    SMF 2.1.6 Update    1.0
22    Reply Button In Every Message    1.0
23    Automatic Attachment Rotation (and Resize)    6.24
24    TinyPortal    3.0.2
25    Optimus    2.13
27    Alternate User Posting    2.1.2
28    Message Bookmarks    0.9.5
29    Stop Forum Spam    1.5.6
30    Unlimited Attachments Permission    1.1
31    FJR-club Menu-opties    1.4
32    FJR-club Clubleden boards    1.0

[Aleksi "Lex" Kilpinen]

Moved to bug reports for discussion, so this doesn't get lost in the middle of support topics.

[@rjen]

Any idea what lies at the core of this issue? The file itself is not changed since 2.1.3 so it must be another file causing a call resulting in the 500 error.

The other forum on the same server still works. Thinking it may have been related to specific data in a post?

[Illori]

if you are getting a 500 error it should have logged something in the server error log, can you check?

[@rjen]

Exactly that

Fatal error: Uncaught Error: Call to undefined function idna_maps_not_std3()

[@rjen]

To be precise:

[Sun Jun 29 03:01:20.307456 2025] [lsapi:error] [pid 4115853:tid 140209476306688] [client 2a10:3781:a04:1:d420:111e:5da1:4f61:57031] [host www.fjr-club.nl] Backend fatal error: PHP Fatal error:  Uncaught Error: Call to undefined function idna_maps_not_std3() in /home/deb77453/domains/fjr-club.nl/public_html/Sources/Class-Punycode.php:537

[shawnb61]

Logged:
https://github.com/SimpleMachines/SMF/issues/8711

[VadiKO]

I also got the following error on one of my forums some time after updating to 2.1.6 - Call to undefined function idna_maps_not_std3()
The forum is down.
Is there already a solution?
Thank you.

You cannot view this attachment.

[@rjen]

Temp solution: remove the two lines of code as mentioned in post one

[riou]

This bug also killed all pages that rely on SSI as well

Temp solution: remove the two lines of code as mentioned in post one

This did bring it back

[@rjen]

That's the fourth forum going down because of this bug 

[Kjell H.]

Same error on my end. Forum is down.

[Kjell H.]

I followed the instruction in the first post and the forum is back up.

[marcomilano]

Just been greeted with this fatal error on my forum on every page.

Fatal error: Uncaught Error: Call to undefined function idna_maps_not_std3()

You cannot view this attachment.

I've had to comment out the call to the function in Class-Punycode.php, Lines 536/537.

SMF 2.1.6.

it works, thanks!

[adamcook]

I saw the same in my forum - the web server just returned HTTP 500, though. Digging into the PHP error log enabled me to see the same exception about calling an undefined function.

Commenting out the function call got the forum running again.

We updated our forum last week to 2.1.6 and it didn't immediately seem to go down. I'm not sure how long after it went down, but it wasn't immediately after applying the update.