Check him out medically like shepherdmom recommended...
And if he's ok then you need to up YOUR game on the positive only training. If you aren't using tons of treats/toys and calm praise daily, then that's where you need to start.
Plus if you are male with that deep voice, you need to know that just a normal tone may be off putting to him. There is a reason you hear all those Police officers and Military K-9 Trainers have that high pitched crazy happy tone in their voices. It's because the TONE of the voice is way more important than what the words are saying to our pups.
Have you started up clicker training? It's a HUGE help to teach us how to train our pups properly. It forces us to reward with treats (and toys) frequently. It forces us to pay attention to whats going on. It makes us be PATIENT (hard for humans, we tend to want to MAKE our pups do something rather than wait for them to figure it out). Initial training has us not talk at all! So our tone won't mess up the dogs thought processes as we have to shut up while they figure it out.
Have you seen this link? If you can read thru and start adding the ideas to your training you will be AMAZED at the changes in your relationship with your dog. Soft dogs ARE a challenge.
But the good news is that 'soft' dogs make us much better dog owners and trainers.
Top Training Expectations for Puppies
MACH3 Bretta Lee Wildhaus MXG MJG MXF MFB TQX HIT CGC TC
Glory B Wildhaus AX, AXJ, XF
"Behind every great man is a woman rolling her eyes." - Jim Carrey