ValueError: The condensed distance matrix must contain only finite values

I am trying to cluster and keep getting "ValueError: The condensed distance matrix must contain only finite values."

I have tried the code below and cannot fix the issue.

df.fillna(0)
df.replace(np.nan, 0)

plt.figure(figsize=(10,3))
%matplotlib inline
plt.style.use('seaborn-whitegrid')
columns = ['hr_starting','coal','gas','hydro','nuclear','oil','other','solar','storage','wind','flywheel','total_gen','thermal_load','total_renewables','gas_percentage_of_thermal_load','philadelphia','congestion_price','energy_price','lmp_price','marginal_loss_price']
x = df[['coal','gas','hydro','nuclear','oil','other','solar','storage','wind','total_gen','thermal_load','total_renewables','congestion_price','energy_price','lmp_price','marginal_loss_price']]

y = df['total_gen']

linked = linkage(x, 'single')

labelList = range(1, 11)

plt.figure(figsize=(10, 7))
dendrogram(linked,
            orientation='top',
            labels=labelList,
            distance_sort='descending',
            show_leaf_counts=True)

plt.xlabel('cluster size')
plt.ylabel('distance')
plt.show()```