Booking not working but no error report


Dear All,

I am not 100% sure if this is the right place to do, but I herited the task of managing the machine booking system of my lab and I only had to do minor code changes to update the list of available machines and add new users etc… I Googled a line of code and ended up in here so it seems that the original scheduler php files that I have originated from here !

However, we recently had to move the hosting of the php files to another host machine, which for some reason that I cannot trace, does not accept new bookings.

It is possible to create a booking event, but the input is not saved in the database and vanishes when I actualize the page. Furthermore, the booking appears in RED, when normally it should be in white when working normally ! (The production server is still hosted on the hold machine so other users can do the booking normally, shown here in white)


I usually get error messages in the Debugger tab of the Web Developper tools, or in the phperror.log / error.log files. However, this time I have absolutely no hint of what could be happening. When inspecting the creation, the line I get is:

div_class =“dhx_cal_event_line_event_12”

With then description of the font, length width and color but nothing more.

Would you happen to know where I could find the line of code involving the change of font to “red and bold” when having an issue ?

I have checked if the issue comes from the Database communication by adding a line sending an error message instead of loading the website if it cannot acces the DB, and I tested it by changing the password (hence not allowing the connection). It sent me the error message as expected. When I put back the right password I have no error message and the website loads perfectly.

Maybe you could have more information than me on how to troubleshoot the issue.

Thank you in advance,



Hello @Puzzle95 ,

It’s hard to suggest what exactly goes wrong without seeing your code o knowing changes you made, but the red coloring of events occurs when the data is parsed incorrectly, here is a short screencast:

So you can check the data format.

Also, if it won’t help as troubleshooting approach, you can check out the following guide:

It also may be helpful, to check our backend integration guides, that may help you to understand how the scheduler work with backend, and how to modify it in future:

Kind regards,


Hello @Siarhei,

Thank your for taking the time to help me, greatly appreciated.
Unfortunately, I seem to have an old version/ mixed with personnal code/ php version and it does not look at all like what you recorded, I cannot really traceback to check the JSON/REST format.

I have been however able to dig a bit further thanks to the troubleshooting protocol and have slightly more information:

On my working version of the scheduler network, when I create an event I have as HXR - Response:

data> <action type=‘inserted’ sid=‘1659445920664’ tid=‘16075’ /action/data>

On my non-working version of the scheduler network I have as HXR - Response:

data> <action type=‘error’ sid=‘1659443889199’ tid=‘1659443889199’ /action/data>

It is the first time I see the occurence of the word “Error” (hooray!) , and the ‘tid’ value is different in format and is the same value as “sid”. Is it a common error that can be tracked ? Do you have anything in mind ?

Thank you again,



Hello @Puzzle95 ,

The error action, means that the backend was unable to handle your request, possibly because of changes you made.

Possibly, as you are using old scheduler version with some customizations(which means that our guides may be not helpful), the best way to fix the issue - is to revert changes, and make them again step-by-step checking on which step updates won’t be handled by the backend and sent to the database.