Warning signs, in order, with the response to each

The signs arrive in this order. The response to the first one decides whether the fifth ever arrives.

#	Sign	What it means	Response
1	"You've reached the weekly invitation limit" earlier in the week than usual	the account's weekly allowance shrank; LinkedIn lowers it quietly for accounts it is watching	halve the invite cap for two weeks
2	Search results stop paging ("commercial use limit")	the account is flagged for search volume	halve the invite cap for two weeks; stop any search-and-invite loop for 48 hours
3	A CAPTCHA or "verify your identity" prompt at login	LinkedIn suspects automation on the session	pause every tool that touches the account for 72 hours; log in by hand from the usual device
4	Invitation notes silently dropped (the invite arrives without the text)	the account is throttled at the note level	check note length first (200 or 300); if lengths are fine, treat as sign 3
5	A temporary restriction	the account is suspended for days to weeks	stop everything for a week; withdraw every pending invite; log in from the usual device only; do not appeal with "I use a tool"

What not to do at each sign

• At sign 1 or 2: do not "use up" the remaining allowance faster. The allowance is the warning.
• At sign 3: do not solve the CAPTCHA from a tool's browser. Solve it by hand, on the device the account normally uses.
• At sign 5: do not create a second account. Two restricted accounts are worse than one, and LinkedIn links them by device and network.

Coming back

After a restriction: a quarter of every cap for two weeks, then half for two more, weekdays only, by hand for the first week. Rebuild the acceptance rate above 30 percent before any tool touches the account again.