PHP is running out of memory. Assuming you have your own DSP, as a workaround you can bypass the following code in your DSP by adding 'false && ’ at the beginning of the conditional. This prevents conversion from JSON to PHP array which was causing it to run out of memory.
File is, from the root of your DSP installation, vendor/kisma/kisma/src/Kisma/Core/Utility/Curl.php line 396