Increase the number of InMails you send daily slowly from day to day.
➔ Here you can find the daily limits
If you don't follow this and increase the number quickly, for example from 0 to 30 InMails per day, the limit set by LinkedIn will be smaller.
When writing InMails on LinkedIn or in services searches, the limit is ideally at least 200.
For writing InMails directly in Sales Navigator, we currently do not know of any limit.