We have just gotten intel that the body has many lines of defence, which explains your MULTIPLE failures.
But if you follow instructions, you will succeed.
Get past the skin, mucus, saliva, stomach acid, cilia and urine. That's your first task. Make sure the antigens are equipped properly to get past those barriers.
Now, the first line of defence is always on-hand to defend the body. You must get past them in order to get access.
Then you will have to get past the second line of defence.
For those who don't know, that's cells, organs and tissue. White blood cells will find and destroy you all if you aren't careful, and there are many types that will overtake you. White blood cells are carried through the body in lymph vessels, tubes in the lymphatic system.