552 5.2.2 — The recipient's inbox is out of storage space (Gmail)
Retrying later can work — at a lower rate, not the same one.
The reply
552 5.2.2 The recipient's inbox is out of storage space.The mailbox exists and is full. Nothing on your side caused it and nothing on your side fixes it — but how long you keep trying is your decision, and an address that has been full for months is usually an abandoned one.
What it means
Ordinarily a soft failure worth retrying for a few days, because the recipient may clear space. Gmail sometimes pairs it with wording about the account being inactive as well, and that combination is the useful signal: a full mailbox that nobody is emptying is an abandoned mailbox, and continuing to send to it does nothing for you except worsen your engagement statistics.
Why it happens
- The recipient's Google storage is full — Gmail, Drive and Photos share one quota, so it is often not mail that filled it.
- The account is abandoned and nobody is clearing anything.
- A shared or role mailbox nobody has owned for a while.
What to do
- Retry on your normal soft-bounce schedule for a few days.
- Suppress the address after it has been full across several sends — at that point it is abandoned, not busy.
- Treat a full mailbox as an engagement signal and drop it from bulk mail even if you keep it for transactional.
- If it is a customer you need to reach, use another channel; more mail cannot arrive.
Questions
Should I keep retrying?
For a few days, yes. Past that it is an abandoned account, and continuing costs you delivery statistics for a message nobody will read.