i have allmost finished my statistical work, , but i get this next warning message when i fitted the null model:

Warning messages:

1: In theta.ml(Y, mu, sum(w), w, limit = control$maxit, trace = control$trace > :

iteration limit reached

2: In sqrt(1/i) : NaNs produced

3: In theta.ml(Y, mu, sum(w), w, limit = control$maxit, trace = control$trace > :

iteration limit reached

4: In sqrt(1/i) : NaNs produced

`wahts the minig of it?`