Joomla! Template AT Jewellery - Item Support

Hi, all the functions of Hikashop is not working on my website : http://www.aunefantaisiepres.be

When you try to edit something or make a checkout --> HTTP 500
www.aunefantaisiepres.be/index.php?option=com_hikashop

by example : http://www.aunefantaisiepres.be/index.php?option=com_hikashop&ctrl=checkout&Itemid=555

The debug mode is active
I've purchased AT Jewellery template in 2018. Can I update the template now, and how?
Hello KOKOLOKOKOLO,
We are sorry, the license for downloading your item is expired, you may extend it from your AS account.

Regards, AS Team.
Hello,
I've purchased new license, downloaded actual template, installed it, and then I updated all components. But I cannot update the core joomla - the version which came with the template is Joomla 3.8.8, and it should be updated to 3.9.23, but when I click to "Update" in joomla-back-end the white screen shows and nothing is happening. My PHP version is 7.3.25.
Can you pls help me to update joomla?

Regards
Thank you!

I put following line in my .user.ini file (put this file in the joomla-root directory) and I was then able to update joomla:
memory_limit = 128M

Best regards!
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Item Name:
AT Jewellery
Author:
Downloads:
645
Sales:
73
Created:
2016-07-12
Updated:
2019-01-06
Item Version:
3.0.0
$29.00 $21.75
Regular License
This item may be used for a single domain only.
$39.00 $29.25
Extended License

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