Troubleshooting bluetooth over serial

The exercise is to retrieve the model number of a Bluetooth device.

Win10 Bluetooth connection:

Not sure why serial port object s7 fails to fopen. Any actionable suggestions or diagnostic questions are appreciated.

>> s6 = serial('COM6', 'BaudRate', 9600);
>> s7 = serial('COM7', 'BaudRate', 9600);
>> s6

     Serial Port Object : Serial-COM6

     Communication Settings 
        Port:               COM6
        BaudRate:           9600
        Terminator:         'LF'

     Communication State 
        Status:             closed
        RecordStatus:       off

     Read/Write State  
        TransferStatus:     idle
        BytesAvailable:     0
        ValuesReceived:     0
        ValuesSent:         0

>> s7

     Serial Port Object : Serial-COM7

     Communication Settings 
        Port:               COM7
        BaudRate:           9600
        Terminator:         'LF'

     Communication State 
        Status:             closed
        RecordStatus:       off

     Read/Write State  
        TransferStatus:     idle
        BytesAvailable:     0
        ValuesReceived:     0
        ValuesSent:         0

>> fopen(s6)
>> fopen(s7)
Error using serial/fopen (line 72)
Open failed: Port: COM7 is not available. Available ports: COM3.
Use INSTRFIND to determine if other instrument objects are connected to the requested device.

>> fopen(s7)
Error using serial/fopen (line 72)
Open failed: Port: COM7 is not available. Available ports: COM3.
Use INSTRFIND to determine if other instrument objects are connected to the requested device.

>> s6

     Serial Port Object : Serial-COM6

     Communication Settings 
        Port:               COM6
        BaudRate:           9600
        Terminator:         'LF'

     Communication State 
        Status:             open
        RecordStatus:       off

     Read/Write State  
        TransferStatus:     idle
        BytesAvailable:     0
        ValuesReceived:     0
        ValuesSent:         0

>> s6

     Serial Port Object : Serial-COM6

     Communication Settings 
        Port:               COM6
        BaudRate:           9600
        Terminator:         'LF'

     Communication State 
        Status:             open
        RecordStatus:       off

     Read/Write State  
        TransferStatus:     idle
        BytesAvailable:     0
        ValuesReceived:     0
        ValuesSent:         0

>> fprintf(s6, '*IDN?')
Error using serial/fprintf (line 144)
Unexpected error: A timeout occurred during the write operation..

>> fopen(s7)
Error using serial/fopen (line 72)
Open failed: Port: COM7 is not available. Available ports: COM3.
Use INSTRFIND to determine if other instrument objects are connected to the requested device.