Load Problem Nextcloud - Mac Book Air

i have a Nextcloud 14.0.3 on Debian 9
when i use it with a Browser Client it works fine

as soon i do start my MacBook Air, it connect and the load of the server goes up to 10
when i disconect WLAN and reboot the MAC the Load ist still up to 10
only a reboot of the Nextcloud Server brings some help

any idea what the problem?
have a nice day