How did Reconstruction Era cause blacks not able to vote?

The Reconstruction Era initially aimed to grant African American men the right to vote through the 15th Amendment, but various discriminatory practices quickly undermined this progress. Southern states implemented measures such as literacy tests, poll taxes, and understanding clauses, which effectively disenfranchised many Black voters. Additionally, the rise of Jim Crow laws institutionalized racial segregation and further obstructed Black citizens' political participation. As a result, despite legal advancements, systemic barriers perpetuated their exclusion from the electoral process.