How to go to the next found result when using the less command on a log file in Linux?

The answer is in the manual, man less:

       n      Repeat previous search, for N-th line containing the last
              pattern.  If the previous search was modified by ^N, the
              search is made for the N-th line NOT containing the
              pattern.  If the previous search was modified by ^E, the
              search continues in the next (or previous) file if not
              satisfied in the current file.  If the previous search was
              modified by ^R, the search is done without using regular
              expressions.  There is no effect if the previous search
              was modified by ^F or ^K.

       N      Repeat previous search, but in the reverse direction.