Ordinal response with monotonic predictor

I ran the model using the above priors. The good thing is that I got simplex results. However, the Rhats are not good.
here is the results

Data: bodi (Number of observations: 2622) 
Samples: 4 chains, each with iter = 2000; warmup = 1000; thin = 1;
         total post-warmup samples = 4000

Group-Level Effects: 
~idno (Number of levels: 898) 
              Estimate Est.Error l-95% CI u-95% CI Rhat Bulk_ESS Tail_ESS
sd(Intercept)     4.13      0.14     3.86     4.41 1.01      457     1116

Population-Level Effects: 
                  Estimate Est.Error l-95% CI u-95% CI Rhat Bulk_ESS Tail_ESS
Intercept[1]        -11.12      0.50   -12.11   -10.17 1.01      949     1834
Intercept[2]         -8.07      0.30    -8.67    -7.51 1.01      703     1816
Intercept[3]         -5.67      0.21    -6.10    -5.28 1.02      422     1057
Intercept[4]         -3.56      0.18    -3.92    -3.20 1.03      262      803
Intercept[5]         -1.82      0.17    -2.15    -1.50 1.04      219      514
Intercept[6]         -0.06      0.16    -0.38     0.24 1.04      125      498
Intercept[7]          1.40      0.16     1.08     1.71 1.04      130      560
Intercept[8]          2.97      0.17     2.64     3.30 1.03      172      687
Intercept[9]          4.49      0.19     4.13     4.87 1.03      259      983
Intercept[10]         5.97      0.21     5.57     6.40 1.02      373     1267
Intercept[11]         7.60      0.25     7.14     8.08 1.02      554     1719
Intercept[12]         9.49      0.31     8.92    10.10 1.01      650     2034
Intercept[13]        11.21      0.41    10.43    12.04 1.01     1412     2826
Intercept[14]        13.22      0.66    12.04    14.59 1.00     2611     2885
       mochf          0.50      0.08     0.34     0.65 1.00      915     1622

Simplex Parameters: 
                      Estimate Est.Error l-95% CI u-95% CI Rhat Bulk_ESS Tail_ESS
      mochf1[1]        0.16      0.09     0.03     0.36 1.00     2083     2314
      mochf1[2]        0.84      0.09     0.64     0.97 1.00     2083     2314

Samples were drawn using sampling(NUTS). For each parameter, Bulk_ESS
and Tail_ESS are effective sample size measures, and Rhat is the potential
scale reduction factor on split chains (at convergence, Rhat = 1).

The good news is I got the simplex result but not good Rhat
Should I change the priors’ values?
Thanks