Try selecting "Do not mount" in VeryCrypt and then mount the disk manually. Open terminal:
diskutil list
/dev/disk5 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: VERACRYPT +10.2 MB disk5
diskutil mount /dev/disk5
Volume VERACRYPT on /dev/disk5 mounted
There seems to be a problem with FAT32 and exFAT filesystems. After manually mounting the volume, I created a new with HFS+. I was able to mount it without any problems. I'm using Mac OSX High Sierra.