Custom fields on some products are not working

[cvrak]

Hi,
I face a strange problem. In a specific category, some products with custom fields give "Error updating page" error message when I try to select a custom field.
At the same category, some products with custom fields are working fine.
What is happening?

The URL of the page is (Its in Greek)
https://4epoches.com/%CE%B1%CF%81%CE%B4%CE%B5%CF%85%CF%84%CE%B9%CE%BA%CE%AC/%CE%B5%CE%BE%CE%B1%CF%81%CF%84%CE%AE%CE%BC%CE%B1%CF%84%CE%B1-%CF%83%CF%85%CE%BD%CE%B4%CE%B5%CF%83%CE%BC%CE%BF%CE%BB%CE%BF%CE%B3%CE%AF%CE%B1%CF%82
The two first products (among others) give the error message, while the four last ones are working fine.

Pls advice
Thanks


Joomla 3.9.3
VM 3.4.2
php 7.1.27

[Studio 42]

I think it's a problem with the URL and russian characters.
You have not a real error but a 404 not found URL

[cvrak]

What do you mean Russian characters? Its a Greek site, with Greek characters.
How you get 404 not found error?
The error message I'm referring to is a pop up message

Pls advice
Thanks

I think it's a problem with the URL and russian characters.
You have not a real error but a 404 not found URL

[cvrak]

Now I've found out that when I'm in product details, custom fields are working fine.
Isn't it strange?

Pls advice
Thanks