`factor_analysis <- fa(items, nfactors = 4, rotate = "varimax") 

In smc, smcs > 1 were set to 1.0
In smc, smcs > 1 were set to 1.0
In smc, smcs > 1 were set to 1.0
Error messages:
1: In cor.smooth(r) : Matrix was not positive definite, smoothing was done
2: In fa.stats(r = r, f = f, phi = phi, n.obs = n.obs, np.obs = np.obs,  :
  The estimated weights for the factor scores are probably incorrect.  Try a different factor score estimation method.
3: In fac(r = r, nfactors = nfactors, n.obs = n.obs, rotate = rotate,  :
  An ultra-Heywood case was detected.  Examine the results carefully`

I calculated a factor analysis (FA) for two questionnaires. They are both very similar. The first FA went very well but the second is showing a lot of error messages. What could be the problem?