Ranges entered the Europa League first qualifying round last summer where they were defeated over two legs by Luxembourg side Progres Niederkorn.
Having won the first-leg at Ibrox 1-0, the team fell to a 2-0 loss in the return, an evening which ended with Caixinha standing in a bush debating with irate fans.
Former Rangers forward Miller recalled the club’s preparations for the match and during pre-season in an interview with the BBC, as he branded the defeat “an absolute embarrassment”.
“It is an embarrassment to play a part in it,” he said. “We got beat 2-0 in an away leg which was unforgiveable. What happened? We never turned up on the night, conceded sloppy goals, horrendous goals.
“You’ve got however many new signings that were made, different cultures, different nationalities coming into a team. You’ve had three weeks prep going into a game. I don’t think we were prepared right for it. I don’t think the pre-season was proper either. There was so much wrong going into it.
“You’re going into a game of football, are young going to be prepared three weeks into the season, no you’re no. But you’ve got to go into that game and win, find a way to win. We never did the job sufficiently in the first-leg, we should have won by more. The second-leg we just never turned up.”
Miller left the club following the expiry of his contract. His last match was in a 4-0 win over Dundee at the start of April.
The 38-year-old, along with club captain Lee Wallace, were suspended following an incident after the club’s 4-0 loss to Celtic in the Scottish Cup semi-final. Both players were fined by the club, something which the duo are appealing.
Miller told the BBC that he would open up one day about his final season at Ibrox and to defend the “defamation” of his character.
The player has vowed to continue playing with offers from home and abroad with both Aberdeen and Livingston linked to the player. He has been touted as a potential player/manager for Premiership new boys Livi, a prospect which “intrigues” Miller.