DIAGNOSIS The red blinking light with beeps is the tank error alert. The most likely cause is that either the clean water tank or dirty water tank isn't seated perfectly.
FIX The fastest fix is a full tank reseat. Unplug the machine. Remove BOTH the clean water tank and the dirty water tank completely. Check the dirty tank's float filter—make sure it's not jammed or stuck. Reinstall the dirty water tank first, pressing firmly until you hear a definitive click. Then install the clean water tank, again pressing down until it clicks into place. Plug it back in and try.
IF THAT DIDN'T WORK Check for a clog in the dirty water tank's air path. The float assembly inside that tank can get gunked up. Remove it, rinse it thoroughly under warm water, and let it dry completely before reinstalling the entire tank.
HEADS UP Never run the machine with either tank removed or even slightly ajar. It's designed to shut down immediately to prevent motor damage, which triggers this exact error.