Hi
The support team have suggested I ask for help on the forums on this, so here goes :-)

It recently came to light that forms (2.4 and 2.5 version) connected to Maiilchimp are no longer working for us.
They still submit to us, just not to Mailchimp.
The user sees the error message:
"Your form could not be submitted for the following reason(s):
Communication with MailChimp failed. Check the error log."

I do not know where the error log is and as a free MC user there is no support.
As a temporary measure, I thought I could comment out the code in the form.cfg.php file, but cannot find which code I need to comment out to keep the forms working but just not bother trying to connect to MC so users will not get the error message.
Can anyone identify which code needs to be commented out/removed to do this?
Or better still, have a fix to get them working again? :-)

Many thanks!

Look within your form folder on your server for the error log.

Thanks for the tip Eric - after searching the form files I found an error log called fb_error.log.php in the 'storage' folder.
The error shows here as:
(Timestamp for each occasion:) MailChimp returned this:

Does nothing after the 'MailChimp returned this' give a clue about what the issue is?
(The log also shows the first instance was last September 27th)

Appreciate any suggestions to resolve this - thanks!

Has your php version changed?

Hi Eric
So far back, I do not know if it was changed at that time.
My server is running php 7 but domains with the forms on have:
SetEnv PHP_VERSION 53 in the .htaccess for those sites.

What does CC support have to say about it?

Thanks for your further post Eric - it was CC support who suggested I post in the forums, at the point where I asked what was the code I needed to comment out in the form.cfg.php for now to stop existing forms trying to pass to MC.

Previous to that, they suggested I buy the latest Web Form Builder or contact MC.
As a free MC user there is no support option for any issues, so I am pretty stuck it seems at present :-(

Any further insights welcome!

Ok, I see your using free option. If I get a chance in the next few days, I'll take a look at this a little further.

Can you share your fb file of a form that's not working?

Many thanks Eric :-)
When you say 'fb file', do you mean the fb_error.log.php file?
The content of one of those from a form which has stopped working is below (if you meant something else, do let me know :-)
<?php echo 'Access denied.'; exit(); ?>
Tue, 27 Sep 2016 17:23:48 +0000: MailChimp returned this:
Tue, 27 Sep 2016 17:24:12 +0000: MailChimp returned this:
Thu, 29 Sep 2016 19:03:20 +0000: MailChimp returned this:
Thu, 29 Sep 2016 19:03:48 +0000: MailChimp returned this:
Thu, 29 Sep 2016 19:04:15 +0000: MailChimp returned this:
Thu, 29 Sep 2016 19:07:33 +0000: MailChimp returned this:
Tue, 01 Nov 2016 12:25:38 +0000: MailChimp returned this:
Tue, 01 Nov 2016 12:25:46 +0000: MailChimp returned this:
Tue, 01 Nov 2016 12:26:08 +0000: MailChimp returned this:
Tue, 01 Nov 2016 19:53:23 +0000: MailChimp returned this:
Tue, 01 Nov 2016 21:02:27 +0000: MailChimp returned this:
Wed, 18 Jan 2017 11:27:06 +0000: MailChimp returned this:
Wed, 18 Jan 2017 11:27:13 +0000: MailChimp returned this:
Wed, 18 Jan 2017 11:27:30 +0000: MailChimp returned this:
Mon, 30 Jan 2017 12:53:14 +0000: MailChimp returned this:
Mon, 30 Jan 2017 12:53:27 +0000: MailChimp returned this:
Mon, 06 Feb 2017 15:35:27 +0000: MailChimp returned this:
Tue, 07 Feb 2017 06:55:44 +0000: MailChimp returned this:
Fri, 10 Feb 2017 09:42:18 +0000: MailChimp returned this:
Fri, 10 Feb 2017 09:42:27 +0000: MailChimp returned this:
Fri, 10 Feb 2017 09:42:33 +0000: MailChimp returned this:
Mon, 13 Mar 2017 15:29:51 +0000: MailChimp returned this:
Mon, 13 Mar 2017 15:30:11 +0000: MailChimp returned this:
Tue, 04 Apr 2017 20:25:16 +0000: MailChimp returned this:
Tue, 04 Apr 2017 20:25:34 +0000: MailChimp returned this:
Tue, 04 Apr 2017 20:26:32 +0000: MailChimp returned this:
Thu, 13 Apr 2017 17:04:36 +0000: MailChimp returned this:
Thu, 13 Apr 2017 17:05:29 +0000: MailChimp returned this:
Thu, 13 Apr 2017 17:06:28 +0000: MailChimp returned this:
Mon, 17 Apr 2017 14:13:45 +0000: MailChimp returned this:
Mon, 17 Apr 2017 14:14:18 +0000: MailChimp returned this:
Mon, 17 Apr 2017 14:14:39 +0000: MailChimp returned this:
Mon, 17 Apr 2017 14:14:47 +0000: MailChimp returned this:
Tue, 18 Apr 2017 12:55:07 +0000: MailChimp returned this:
Tue, 25 Apr 2017 08:22:32 +0000: MailChimp returned this:
Tue, 25 Apr 2017 08:23:09 +0000: MailChimp returned this:
Tue, 25 Apr 2017 08:27:08 +0000: MailChimp returned this:
Tue, 25 Apr 2017 08:27:31 +0000: MailChimp returned this:
Wed, 24 May 2017 14:01:18 +0000: MailChimp returned this:
Thu, 01 Jun 2017 15:16:26 +0000: MailChimp returned this:
Tue, 20 Jun 2017 12:07:22 +0000: MailChimp returned this:
Tue, 20 Jun 2017 17:06:18 +0000: MailChimp returned this:
Mon, 26 Jun 2017 21:37:30 +0000: MailChimp returned this:
Mon, 26 Jun 2017 21:38:00 +0000: MailChimp returned this:
Mon, 26 Jun 2017 21:38:21 +0000: MailChimp returned this:
Mon, 26 Jun 2017 21:41:37 +0000: MailChimp returned this: