Pi-Hole impact on emails

These tools can help you determine which domains are being blocked that interfere with your content:

What OS is the client on which you are viewing emails running? MacOS has some particular settings to get emails to load.

Edit:

Please upload a debug log and post just the token URL that is generated after the log is uploaded by running the following command from the Pi-hole host terminal:

pihole -d

or do it through the Web interface:

Tools > Generate Debug Log