it is working when i given single as IMAGE_INSTALL_append_pn-mdm9x28-image-minimal = " openvpn". we need to add other recipes also.
then which one is making the problem?
It could be the generated binary is too big, you can go to ./meta-swi/meta-swi-mdm9x28/conf/machine/swi-mdm9x28.conf
change UBI_ROOTFS_SIZE ?= "48MiB"
If the image is too big to put into module, you might need to consider to put the binary in userapp partition.