The tool requires a direct USB connection. You must disable your antivirus (false positives are near-certain because the tool hooks directly into USB low-level drivers). Experienced users run it on an old laptop with no network connection.
The Epson L5190 keeps track of the waste ink generated during head cleanings via an internal counter. When this counter hits 100%, the printer locks itself to prevent ink from overflowing out of the physical waste pads. The Adjustment Program epson l5190 adjustment program reset tool
Zeroes out the internal counter (Main pad and Platen pad). The tool requires a direct USB connection
Standard resets available through the printer's hardware or official software generally do not address the "Service Required" error: epson l5190 adjustment program reset tool