Steps to deactivate all the plugins via cPanel

Step 1: Login to your cPanel.
Step 2: Expand the Public_html folder, and navigate to the /wp-content/plugins folder.
Step 3: Right click on the /wp-content/plugins folder and rename it like plugins.old.
Step 4: This will deactivate all of the plugins at once.
Step 5: Now, reactivate plugins folder again by renaming back to plugins.