Same problem and I don't know how to solve.. Here an example of cell that has always worked correctly but from yesterday it stopped.

# Compute the correlation matrix
correlation_matrix = data.corr()

# Set up the matplotlib figure
plt.figure(figsize=(14, 10))

# Draw the heatmap with the mask and correct aspect ratio
sns.heatmap(correlation_matrix, annot=True, fmt=".2f", cmap='coolwarm', 
            cbar_kws={"shrink": .8}, linewidths=0.5, linecolor='black')

# Add a title
plt.title('Correlation Matrix', fontsize=16)

# Adjust the font size for better readability
plt.xticks(fontsize=12, rotation=45, ha='right')
plt.yticks(fontsize=12)

# Show the plot
plt.show()