Hi @fountaini!
There should be an error in your website logs. Check the error log on your server. If you can’t find the log, please contact your host.
Enable wp_debug and wp_debug_log and after an error, look at wp-content/debug.log to see if anything gets logged there. https://wordpress.org/support/article/debugging-in-wordpress/
You can also try this: Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.
Thank you. I was not looking in the right place to delete that Pinterest button. I fixed my problem by going to Appearance > theme options. Still no clue what the error was about with the widget page and I will try to figure it out later.
Thanks again for your fast response.
Ingrid.