Hello

Thank you for your query & apologies for the inconvenience. Actually, this type of problem can occur for a third-party extension, and it is not relevant with our product. Could you please check the possible solutions in the link below?

https://forum.joomla.org/viewtopic.php?f=812&t=990901

Hello Ariba....

I had studied the link of the Joomla forum. Excelent !!

I found the same error in the same file in the same line 149...

() JROOT/libraries/src/HTML/HTMLHelper.php:149

I disabled the obsolete plugins that we don´t use a time ago and We was been disabled (in J3.10.x) before the migration:

JSN_EASYSLIDER_PLUGIN_CONTENT_TITLE &
JSN_EASYSLIDER_PLUGIN_BUTTON_TITLE

These plugins was enable in J4.
After the disabled I could access to edit the article well.

Thanks for your help.

Hello

Thank you for letting me know that your problem has been solved :)

Please do let me know if you have any other related query, I would be happy to help. If there is no other query, kindly accept the most useful answer that helped you, in order to resolve and close the post.

Have a great day!