Cisco Port – Why Port is Not Connected but Other Side Comes Up

On my Cisco Catalyst 3850 there is a SFP Module which is connected to another device, the port on the Other device (vendor equipment) come up but my interface is still down. The DOM Information show me receive and transmit pegel and if I do a shut command on that interface the other side goes down.

This is the config of that port:

interface GigabitEthernet1/0/8
 description port1
 no switchport
 ip address 10.1.1.80 255.255.255.254
end

But the port is still down:

sh int gi1/0/8 status

Port      Name               Status       Vlan       Duplex  Speed Type 
Gi1/0/8   port1   notconnect   routed       full   1000 1000BaseLX SFP

And on transceiver detail page there is everything fine:

#sh int gi1/0/8 transceiver detail   
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
mA: milliamperes, dBm: decibels (milliwatts), NA or N/A: not applicable.
++ : high alarm, +  : high warning, -  : low warning, -- : low alarm.
A2D readouts (if they differ), are reported in parentheses.
The threshold values are calibrated.

                              High Alarm  High Warn  Low Warn   Low Alarm
          Temperature         Threshold   Threshold  Threshold  Threshold
Port       (Celsius)          (Celsius)   (Celsius)  (Celsius)  (Celsius)
--------- ------------------  ----------  ---------  ---------  ---------
Gi1/0/8     39.7                95.0        90.0       -40.0      -45.0

                              High Alarm  High Warn  Low Warn   Low Alarm
           Voltage            Threshold   Threshold  Threshold  Threshold
Port       (Volts)            (Volts)     (Volts)    (Volts)    (Volts)
---------  ---------------    ----------  ---------  ---------  ---------
Gi1/0/8    3.32                  3.60        3.50        3.10       3.00

           Optical            High Alarm  High Warn  Low Warn   Low Alarm
           Transmit Power     Threshold   Threshold  Threshold  Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm)      (dBm)
---------  -----------------  ----------  ---------  ---------  ---------
Gi1/0/8     -5.2                -1.0        -1.9       -10.0      -11.0

           Optical            High Alarm  High Warn  Low Warn   Low Alarm
           Receive Power      Threshold   Threshold  Threshold  Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm)      (dBm)
-------    -----------------  ----------  ---------  ---------  ---------
Gi1/0/8     -6.8                -1.9        -2.9       -24.9      -26.0

I change the SFP Module but still the same, also change the port with the same result. How can I troubleshoot this issue.

It is a little bit strange to me that the Port on the other device comes up but my device is still down.