I'm growing my LinkedIn network for some time already and I send like 100 connection invites through sales now a day. Everything was fine for a few months, but last week or two I sometime encounter a problem - when I'm trying to send invite, I'm every time being asked for user's email in order to proceed. Next day I usually can move on with sending invites as usual.
I could not find any information related to limit of neither invites per day/week/anything, nor pending invites, which I actually remove time to time.
Are there any known rules or limits that I should respect in order to not get this?