Question

What caused problems during grant's presidency apex?

Answer 1

Grant presidency was rocked by series of corruption scandals
 An examination of Grant presidency reveals many scandals and fraudulent activities associated with persons within his administration, including his cabinet, that was in continual transition, divided by the forces of political corruption and reform. Grant problems emanates from factors such as the spoil system.

Answer 2

There were problems of corruption and bad governance that plagued the Ulysses S. Grant presidency.

Grant had granted positions in his administration to people he thought he could rely on, rather than choosing them based on their merits and qualifications.  The poor governance and scandals included members of his cabinet as well as other government agencies.  

Reform movements began to appear in response to the corruption in the Grant administration, not only in the Democratic Party, but also among Republicans.  The Liberal Republicans were a faction that split from Republican Party in 1872, to oppose the reelection of Grant.