Unable to open files in a drive mounted on DOS due to permission issues

Question

I have recently installed Ubuntu 17.04 after formatting and creating new partitions. One of them is mounted on /dos (fat 32).

The issue is whenever I copy a file in that drive I am unable to open the files from the users that i am logged in.

I tried changing the owner and group but it didn't work. (Owner is root and group plugdev).

I have tried adding my user into the group plugdev but still it didn't solve the problem.

From few posts (not sure if I understood correctly) I tried changing umask=000 and gid=1000 but it also didn't solve the issue.

Below are some of the details. Please advise and let me now if i haven't mentioned any relevant information in the question.

    vaibhav@vaibhav-Aspire-V5-571:/dos$ df -h
    Filesystem      Size  Used Avail Use% Mounted on
    /dev/sdb5       314G  192G  122G  62% /dos

    vaibhav@vaibhav-Aspire-V5-571:/dos$ cat /etc/fstab
    # /dos was on /dev/sda5 during installation
    UUID=1189-A5DC  /dos            vfat    utf8,umask=007,gid=46 0       1


    vaibhav@vaibhav-Aspire-V5-571:/dos$ ls -lrt
    total 192
    drwxrwx---   2 root plugdev 32768 Aug 11 13:36 UNIX
    drwxrwx--- 107 root plugdev 32768 Aug 25 13:12 eng

    vaibhav@vaibhav-Aspire-V5-571:~$ lsblk -f    
    NAME   FSTYPE   LABEL UUID                                 MOUNTPOINT    
    loop0  squashfs                                            /snap/core/2462    
    loop1  squashfs                                            /snap/vlc/4    
    loop2  squashfs                                            /snap/core/2774    
    sdb                                                            
    ├─sdb1 vfat           11B9-AD0D                            /boot/efi    
    ├─sdb2 ext4           d06b0055-fafd-4b99-b478-00999d74c456 /    
    ├─sdb3 swap           e9dd09a0-0212-460d-8c0e-265dab801011 [SWAP]    
    ├─sdb4 vfat           117A-D59B                            /windows    
    └─sdb5 vfat           1189-A5DC                            /dos    
    sr0                                                        

vaibhav@vaibhav-Aspire-V5-571:~$ mount | grep -E '^/dev'    
/dev/sda2 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)    

/dev/sda5 on /dos type vfat (rw,relatime,gid=46,fmask=0007,dmask=0007,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)    

/dev/sda1 on /boot/efi type vfat (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)    

/dev/sda4 on /windows type vfat (rw,relatime,gid=46,fmask=0007,dmask=0007,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)