Fix #2370, minor typos and spelling mistakes
diff --git a/library/error.c b/library/error.c
index 12312a0..c596f0b 100644
--- a/library/error.c
+++ b/library/error.c
@@ -567,7 +567,7 @@
         if( use_ret == -(MBEDTLS_ERR_X509_BUFFER_TOO_SMALL) )
             mbedtls_snprintf( buf, buflen, "X509 - Destination buffer is too small" );
         if( use_ret == -(MBEDTLS_ERR_X509_FATAL_ERROR) )
-            mbedtls_snprintf( buf, buflen, "X509 - A fatal error occured, eg the chain is too long or the vrfy callback failed" );
+            mbedtls_snprintf( buf, buflen, "X509 - A fatal error occurred, eg the chain is too long or the vrfy callback failed" );
 #endif /* MBEDTLS_X509_USE_C || MBEDTLS_X509_CREATE_C */
         // END generated code