The mail server doesn't have enough storage space to accept your message. This may be temporary.
SMTP error 452 indicates storage-related issues on the receiving server:
The recipient's mailbox has reached its storage limit.
The mail server's storage has run out of space.
Your message with attachments is too large for the remaining space.
Let them know their mailbox is full. They need to delete old messages or increase their quota.
Remove or compress attachments. Use file sharing services for large files instead.
Server storage issues are often temporary. Your mail server will automatically retry.
452 4.2.2 Mailbox full
452 Insufficient system storage
452 4.3.1 Not enough disk space