If you are using "LiteSpeed" plugin, you may encounter some issues with Checkout page when visiting the checkout. This is due to aggressive page caching (which is a good thing!), but it can be easily resolved by excluding the checkout page URI from cache plugin.
You need to exclude checkout pages by following these instructions-
Step 1: Note down the slug of your checkout page from here
Step 2: Open the settings of "LiteSpeed Cache"
Step 3: Jump on the “Exclude” tab.
Step 4: Scroll down the exclude page and locate for "Do Not Cache URIs"
Step 5: To exclude “checkouts” pages enter your noted checkout page slug (from step 1) with special characters as shown in screenshot: “/checkouts/”
Step 6: Scoll down the page and click on "Save Changes" button to update the settings.
Note: By default, Checkout page's slug is "checkouts". If you had changed the checkout pages slug for any reason get the slug from Global Settings > Miscellaneous tab > Checkout Page Slug