I have 26 custom fields in a group intended for a custom post., and am unable to add the two additional fields I need. I read through some old comments, and saw that there is no limit on custom fields, and that server memory may be the cause. Checked with my server-walla, and he laughed..."we got plenny memory, man" was the response.
If you can provide a copy of your site I can install locally and try and see if I run into the same problem on another server.
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You can paste a link to the duplicator packages on dropbox or similar here (they will be private), or maybe use All in One WP Migration if your server has problems with Duplicator.
I removed your site credentials from your last reply, please only share sensitive info when a private reply has been set up for you as these are public forums.
I could see the problem on your site when trying to edit the custom field group myself, the "Save Field Group" button is inactive, clicking it does nothing (it is supposed to submit the form group details via an ajax request, but the browser console shows this is not happening, the button is inert).
So it is unlikely to be related to your server memory settings, where you would expect to see the save button submit the field group details but then a PHP memory error to be reported on the server.
I tried deleting a field then saving the field group, and that did not work either, so there is nothing magic about the number 28.
It could be related to some other change on your site.
Is this a staging site (or do you have one)?
Could you confirm that the problem still happens after ruling out conflicts by disabling all plugins except Types and switching theme to twentytwenty?
Depending on what you find, I may need to take a copy of your site.
I have 19 other sites on this server, all running "The Gem" theme. We have tweaked the plugin inventory several times, and allow only the current inventory. Casdev is both the build and production server. Once a site is ready, we simply change DNS data. I do have a site on that server, which you can do whatever you want with, the Casdev Sandbox. I will tell my work-study students to stay off that instance until you have done your work. Same creds.
There is a problem with your Link 1 URL field, which has text for the default value (and an error, see screenshot). The default value must be a valid URL, I don't think you meant to put text there.
If you fix that you'll be able to save the field group with new fields.
(I'm not sure how you were able to save it like that in the first place.)
