更正以下句子中的语法错误并解释错误的原因
He don't like pizza.
"don't" should be changed to "doesn't" since the subject "He" is third person singular and requires the third person singular form of the verb "to do." 

Corrected sentence: He doesn't like pizza.

The error is a subject-verb agreement mistake. The verb "like" needs to agree with its subject "He," which requires the third person singular form of the verb "does" (i.e. doesn't) instead of the plural form "do."