Could you please provide your Site Health information to help us determine what might be causing this problem? To get that, you can go to your WordPress dashboard area and go to: Tools > Site Health > Info, then Press the “Copy site info to clipboard” button, and paste the results here.
The error says that on line 14 of content/themes/wp-bootstrap-starter-child/single-work.php, a variable which was expected to be an array containing an ID did not contain any value for the key ID.
In that file on that line, there will likely be some variable written like $variable_name['ID']
For whatever $variable_name is, likely $post or similar, one should then consider where the values for that variable came from in previous lines.
There may also be formatting / santization issues causing problems on the site, as this content on the linked page is outputting < and > using < and >, causing the HTML to not work as intended. This usually happen when an admin user puts HTML into a field intended text content, where the input field has been set to not accept HTML tags.
<p class="client-desc">International Federation of Red Cross and Red Crescent Societies (IFRC)
<a href="http://go.ifrc.org" target="_blank" rel="noopener">http://go.ifrc.org</a></p>
