Hotspot Mac Cookie Not Found While device mac not changed

RouterOS General
1

When I login to MikroTik hotspot via user/voucher, sometimes my device make is not changed but my Mac cookie is not available in MikroTik. Then MikroTik says me to login again. My routeros version 7.19.1

Notes:

Mac Cookie Timeout 30 Days

Dhcp Lease time 1 Day

Hotspot idle time out 5 Minutes

Hotspot keepalive time out 2 Minutes

Address per mac 2

2

make =>MAC ?

You have disabled random MAC?

3

Yes, I don't use random mac. My mac is fixed but sometimes Mikrotik delete my mac-cookie.