Ports going up and down for no apparend reason

[alxlgtl]

I manage a ES-2126P+ switch and for some reason port 26 is going up and down plus a random port from the rest.
The log reports

100,Wed Oct 09 09:08:11 2019,Link Down [Port 26]
101,Wed Oct 09 09:08:01 2019,Link Down [Port 26]
102,Wed Oct 09 09:08:00 2019,Link Up [Port 26]
103,Wed Oct 09 09:06:59 2019,Link Up [Port 26]
104,Wed Oct 09 09:06:59 2019,Link Down [Port 26]
105,Wed Oct 09 09:05:59 2019,Login [admin]
106,Wed Oct 09 09:04:28 2019,Link Up [Port 26]
107,Wed Oct 09 09:04:28 2019,Link Down [Port 26]
108,Wed Oct 09 09:04:14 2019,Link Down [Port 26]
109,Wed Oct 09 09:04:14 2019,Link Up [Port 26]
110,Wed Oct 09 09:04:04 2019,Link Down [Port 26]
111,Wed Oct 09 09:04:03 2019,Link Up [Port 26]
112,Wed Oct 09 09:03:17 2019,Link Up [Port 26]
113,Wed Oct 09 09:03:17 2019,Link Down [Port 26]
114,Wed Oct 09 09:03:01 2019,Link Up [Port 26]
115,Wed Oct 09 09:03:01 2019,Link Down [Port 26]
116,Wed Oct 09 09:02:41 2019,Link Up [Port 26]
117,Wed Oct 09 09:02:41 2019,Link Down [Port 26]
118,Wed Oct 09 09:02:22 2019,Link Up [Port 26]
119,Wed Oct 09 09:02:21 2019,Link Down [Port 26]
120,Wed Oct 09 09:01:44 2019,STP Topology Changed [Port 14]

and keeps going, it never stops for port 26.
I have removed the cable from the port and also disabled it but syslog keeps reporting that port goes up and down.
If you see at the bottom a random port shows also that went up and down and that the STP topology changed.
As a note the device reports temps 62-63C. The poe consumption is minimal. Just in case that heat or power consumption is a factor to considerate.

[C/5]

Hello,
if not the switch, maybe a defect NIC on that device plugged to Port 26? Did you try to plug an other device to see if the behaviour changes?

C/5

[alxlgtl]

Thank you for your device.
It was connected the lan interface of a fax machine.
I have removed the cable and disabled also the port but nothing.
I have reboot the switch also but no it keeps reporting the port to going up and down.