Why is my Shopify checkout button greyed out and unclickable?

Your Shopify checkout button becomes greyed out when a script execution error pauses the DOM load, or when checkout settings are blocked by unconfigured shipping rates, inactive payment gateways, or cart inventory limits.

“This usually comes down to a script conflict freezing the page mid-load, or a checkout setting like shipping rates, payment gateways, or inventory limits that’s not fully switched on. I’ll track down the exact cause and have your checkout button clickable again within 24 hours, for $99.”
— Jeff Bollettino, Managing Director, Ignite Conversions