Make the site useless.

Hello ady1503,
I have Install "views_data_export_phpspreadsheet" (Version: 8.x-1.5) module in Drupal 10.0.1 (language-Spanish). I couldn't able to reproduce the issue mentioned above. Though i was able to reproduce issue https://www.drupal.org/project/views_data_export_phpspreadsheet/issues/3... 🐛 Missing return type error after D10 update Fixed with the same steps mentioned above.
Will you please provide more details and steps to reproduce the issue if it still exists.
Attaching a screenshot for reference.

Hello

I have installed the modules You must activate the modules RESTful Web Services - , Serialization - , Views Data Export - , Serialization (CSV) -

one by one.

In the end install the Views Data Export phpspreadsheet.

The website becomes obsolete and the following appears:

[07-Jul-2023 20:49:35 Europe/Madrid] PHP Fatal error: Declaration of Drupal\views_data_export_phpspreadsheet\Encoder\XlsEncoder::encode($data, $format, array $context = []) must be compatible with Symfony\Component\Serializer\Encoder\EncoderInterface::encode(mixed $data, string $format, array $context = []): string in /home/***/public_html/***.com/web/modules/contrib/views_data_export_phpspreadsheet/src/Encoder/XlsEncoder.php on line 76

Gracias

Automatically closed - issue fixed for 2 weeks with no activity.