In my experience you can try the following steps:
1. Enable domain validation in the General Settings tab so that it links your domain to the QUIC.cloud
2. The Auto Request Cron section means that the plugin will automatically submit your images and optimize for you.
3. The error you encountered is because the previous photo processing request submitted to QUIC.cloud has not been completed. You can wait until it completes and then try again, can’t keep pressing this action. In addition, the number of images per processing will increase gradually according to the number of images that have been successfully processed before, this completely depends on the Litespeed Cache side, they will have point regulation for each image submission and this is not customizable it is automatically calculated from the Litespeed Cache fee. Besides, you will only have a certain number of free optimized images, which you can view at Dashboard or link your account to QUIC.cloud to view.