Blocked Transactions are transactions which were blocked by the fraud settings of the system.
The reason for blocking is normally visible in red under the Verification tab
In cases where you self-manage the fraud, you have various uptions as to how to mitigate the issues.
In cases where your fraud is managed, please see your fraud manager to discuss your specific request and they will evaluate and discuss your settings with you.
In certain cases, the specific fraud policies may not be disclosed, particularly in managed accounts.