Why does Note macro formatting disappear on pages exported to PDF?

[Anahit Korkotyan]

At our company, we use Confluence Server. I am the admin of two spaces.
Recently I noticed that the Note/Info/Tip/Warning macro formatting is not visible on pages exported to PDF. 
I exported pages with note macros from different Confluence spaces in our company. The text was there, but the Note formatting (icon and highlight color) was missing, or the icon was cut off and behind the text.

Here is the published Confluence page.

Here is the same page exported to PDF.

[Thiago Masutti]

Hi @Anahit Korkotyan 
I hope you are well.

When Confluence creates a PDF version of the page it will make connections to the Base URL directly from the backend servers to render some content.

If the process fails to do so, parts of the page may not render as expected on the PDF version.

Based on the screenshot you shared that could be it, which is also described in this feature request: https://jira.atlassian.com/browse/CONFSERVER-74701

Most common scenarios we've seen are related to enforced authentication, either from a Load Balancer (reverse proxy) or a Marketplace App.

Kind regards,
Thiago Masutti