Cannot ping IP address of switch unless it's assigned to VLAN 1

I have an Adtran NetVanta 1531P. This switch uses AOS - *very* similar to Cisco IOS.

The switch's port Gigabit 0/10is connected to my Windows laptop.  The laptop Ethernet port is static assigned 100.100.60.199/24.

(I have attached my 1531P config as an image to this post.)

If I assign IP address 100.100.60.97/24 to "VLAN 1", I can ping it from the laptop.

However, if I instead assign the IP address 100.100.60.97 to "VLAN 901", I cannot ping it.  Even setting "switchport mode trunk" on port Gigabit 0/10 makes no difference.

What am I missing?  Thanks so much. --Walter

HERE IS CONFIGURATION ON THE SWITCH:

! ADTRAN, Inc. OS version R11.10.4

! Boot ROM version R11.2.0.B2

! Platform: NetVanta 1531P, part number 1700571F1

! Serial number LBADTN1704AP198

!

!

hostname "AIB-SANDBOX-AS3"

!

!

!

ip subnet-zero

ip classless

ip routing

!

!

ip route-cache express

!

no auto-config

!

event-history on

no logging forwarding

no logging email

!

no service password-encryption

!

!

!

!

!

!

no dot11ap access-point-control

​

no dos-protection

​

no desktop-auditing dhcp

​

no network-forensics ip dhcp

!

!

!

!

!

!

!

!

!

vlan 1

name "Default"

!

vlan 901

name "VLAN0901"

!

interface gigabit-switchport 0/1

no shutdown

!

interface gigabit-switchport 0/2

no shutdown

!

interface gigabit-switchport 0/3

no shutdown

!

interface gigabit-switchport 0/4

no shutdown

!

interface gigabit-switchport 0/5

no shutdown

!

interface gigabit-switchport 0/6

no shutdown

!

interface gigabit-switchport 0/7

no shutdown

!

interface gigabit-switchport 0/8

no shutdown

!

interface gigabit-switchport 0/9

no shutdown

!

interface gigabit-switchport 0/10

no shutdown

switchport mode trunk

!

interface gigabit-switchport 0/11

no shutdown

!

interface gigabit-switchport 0/12

no shutdown

!

!

!

interface vlan 1

no ip address

ip route-cache express

no shutdown

!

interface vlan 901

ip address 100.100.60.97 255.255.255.0

ip route-cache express

no shutdown

!

!

!

!

!

no tftp server

no tftp server overwrite

no http server

no http secure-server

no snmp agent

no ip ftp server

no ip scp server

no ip sntp server

!

!

!

!

!

snmp-server engine local 800002980300a0c8123456

!

!

!

!

line con 0

no login

!

line telnet 0 4

login

no shutdown

line ssh 0 4

login local-userlist

no shutdown

!

!

!

!

end