Resolve Rate Limiting and Throttling

Emails sending slowly or stalling can mean a receiving server is intentionally slowing acceptance.

Why it happens

Volume (each provider sets its own unpublished thresholds). Reputation (lower reputation means more conservative limits). Recipient-side limits (a mailbox/domain at capacity).

Almost always temporary.

How to work within it

Send in smaller batches — 50–100 with a 2–4 hour gap (Yahoo stricter, use 25–50). Prioritize engaged contacts. Let bounce handling work rather than retrying manually. Confirm authentication is solid.

When to expect it to clear

A few hours to one or two weeks of consistent, well-paced sending. Sustained problems at conservative volumes point to a reputation issue underneath.