bash sh script with user permissions 755, cannot be run - linux

Question

Why can't run it?
If I run it in the following way, it works:
[usuario#MyPC ~]$ sh ./x11vnc.sh
PORT=5900
First, the permissions, so that you can see that it is in 755.
ls -l
-rw-rw-rw- 1 usuario users 4485 dic 2 11:35 x11vnc.log
-rwxr-xr-x 1 usuario users 117 nov 7 14:06 x11vnc.sh
Second,the script file
cat x11vnc.sh
#!/bin/bash
x11vnc -nap -wait 30 -noxdamage -passwd somepass -display :0 -forever -o ~/x11vnc.log -bg -rfbport 5900
Third, I must clarify the structure of the disks
lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 3,6T 0 disk
├─md126 9:126 0 3,6T 0 raid1
│ ├─md126p1 259:3 0 3,6T 0 part /home/usuario
│ └─md126p2 259:4 0 8G 0 part [SWAP]
└─md127 9:127 0 0B 0 md
sdb 8:16 0 3,6T 0 disk
├─md126 9:126 0 3,6T 0 raid1
│ ├─md126p1 259:3 0 3,6T 0 part /home/usuario
│ └─md126p2 259:4 0 8G 0 part [SWAP]
└─md127 9:127 0 0B 0 md
nvme0n1 259:0 0 232,9G 0 disk
├─nvme0n1p1 259:1 0 232,6G 0 part /
└─nvme0n1p2 259:2 0 256M 0 part /boot
I am the user usuario.
I can edit and modify the x11vnc.sh file as I wish, but I can't run it, and I need to run it to include in the auto-start session of the plasma.
[usuario#MyPC ~]$ ~/x11vnc.sh
-bash: /home/usuario/x11vnc.sh: permission denied
Why can't run it?
If I run it in the following way, it works:
[usuario#MyPC ~]$ sh ./x11vnc.sh
PORT=5900

Answer 1

Thank you all, specially to #CharlesDuffy
I change the fstab line from
UUID=16b711b6-789f-4c27-9d6c-d0f744407f00 /home/usuario ext4 auto,exec,rw,user,relatime 0 2
to
UUID=16b711b6-789f-4c27-9d6c-d0f744407f00 /home/usuario ext4 auto,rw,user,exec,relatime 0 2
The position of exec is important, since user also applies noexec. By putting exec after user, you ensure that exec is set. The most important options should be listed last