we will need more steps to reproduce… right now, I am not seeing it…

and the error message does not indicate its coming from simple press.. that is the standard ajax handler for wp…  why do you think its coming from sp???

Thanks for the quickly reply!

There is a chance that the error is caused by a MU plugin that i have running here based on my copy of the installation from our staging server to my local server. I am investigating. 

The reason why I thought it must be SP is because I have no other plugin (except the WP Engine MU plugin) installed and when I deactivate SP the error is gone. 
Will get back to you shortly. 

I deactivated all MU plugins as well and now the only plugin is SP!
I have tested another browser and I am having the same issue. 
In the moment I deactivate SP the Ajax feature shows the new taxonomy instantly whereas it is not updated in the interface (without a reload) if I have SP active. 

What else could be the issue if not SP?

In IE 11 I am getting this error when I have SP active:

XML5635: An XML declaration is only allowed at the beginning of the file. Line: 2, Column 3

So, I cannot replicate your IE 11 issue (took second to get it working since Edge so much nicer)…  Where are you seeing that? and what are you doing?

are you using a specific plugin for setting up your CPTs? or just manually creating the CPT?

for the 500 error generated, anything in the server error log?

if its a sp ajax request, then its likely something else firing an ajax request with the same name…

can you give me more explicit steps you do to recreate the error?

Hi, 

I have created CPT through my functions.php. The setup is standard and works normally just fine. 

And I don’t get the 500 error anymore. I think it was related to something else. It’s a bit confusing here this morning, so I am still trying to eliminate all other possible sources of errors. 

I am just adding new custom taxonomies to my post types and it works but the page is not refreshing without reload and normally it does. In the moment I deactivate SP it works just fine – in Firefox and IE.

The screenshot just shows you where I am at. 
I have attached my functions.php as a txt. 

It may actually not be a purely SP related error but since it is the only plugin that is installed, it must be related to the malfunction of the WP backend. I don’t know what else to say right now. I just tested on our WP Engine live server and I am having the same issue there with an earlier custom post type for events. Also there the refreshing of the taxonomy is not working and only when I reload the page the new taxonomy is showing up. 

Please note: The CPT stuff is just add to the bottom of the file. The rest of the file I never touched. It’s just for test purposes that I use the default theme because I wanted to make sure it is not a theme issue. 

And I do have a warning in my logs, that could be related:
PHP Warning: Invalid argument supplied for foreach() in E:XAMPPhtdocsbbtrswordpresswp-includesclass-wp-post-type.php on line 634

confused… so the ajax error is gone?  but something still not working?

would need to see a call stack for that error as its just a wp routine… need to see who the order of functions…

I have played around with other CPT and taxonomies (we use them here) with no issue… but have not tried the code from your functions.php…  will try to this weekend and see if anything conflicting…  time short with Andy away and moving between two houses, so please bear with us….

Thanks for investigating about this, … what is your name, actually? 

This is not super urgent since the adding of taxonomies actually works.

As soon I have some free time I will add another custom post type and use a standard template that involves more settings than I am currently using and in a kinda “best practice” way. Maybe there is something about the way I register the post types that is part of this problem. (Even though it is be just happening when SP is active, so very much a JS related error). 

Let us know. Steve btw…