Gmail says storage is full and I'm not getting emails. How do I actually free up space?

The 15GB is shared across Gmail, Drive, and Photos, so clear the biggest offenders: 1) In Gmail search 'has:attachment larger:10M' and delete huge emails you do not need. 2) Empty Spam and Trash, they count until purged. 3) Google Photos is usually the real hog. 4) Use one.google.com/storage, which shows exactly what is eating space across all three. Emails flow again once you are back under 15GB, no payment needed.

one.google.com/storage is the single best tool here, it ranks usage across all three services so you are not guessing. Start there.

Do not forget Trash and Spam. Deleting emails does not free space until those are emptied too. Caught me out for weeks.

Photos was 90% of my usage. Switching backup to Storage Saver quality and clearing originals freed gigs instantly.

The 'larger:10M' search in Gmail is gold. A handful of old attachments were eating most of my mail storage.