I promise, this takes only seconds.
For non-Gmail users:
If you’re using any email client other than Gmail, visit whitelist.guide and choose your email provider.
For Gmail users:
If you are using Gmail, the only foolproof way to whitelist a sender is to create a filter that categorizes the sender’s emails as belonging in the Primary inbox. This is not complicated at all, and takes less than 20 seconds. (It can only be done in a browser, though, not in a smartphone app.)
First, click the three dots in the right-hand corner of the email and choose “Filter messages like these.”
Then, make sure the “From” line says “firstname.lastname@example.org” and click “Create filter.”
Finally, check “Never send to Spam,” Categorize the email as “Primary,” check “Also apply filters to matching conversation(s),” and click “Create filter” again.
That’s it! Now you can enjoy receiving the emails you signed up for.