1)Rule 10.2 a. say : if the result of the 1xd6 is one (1), the attack is aborted, and the opportunity to attack passes to his opponent. The player can still try to conduct further attacks later on this turn ....
May the same commander, who fail to attack with a roll of one (1), try to attack again in the same turn ?
2) the same commander can try to support a different combat later in the same turn ?
Thanks for your questions.
1) and 2): Yes to both.