Justin & Hailey Bieber Postpone Wedding Ceremony, Again

Justin and Hailey Bieber are having a hard time finding the perfect day to celebrate their union, because we've learned the couple is postponing their second wedding ceremony ... AGAIN.

Sources familiar with the planning tell us some of the 300 guests who received JB and HB's "save the date" were notified Tuesday that their second round of nuptials is being rescheduled ... for the third time.

We're told the Biebers got some regrets back from certain loved ones who couldn't make it to Los Angeles for the weekend of Justin's birthday at the beginning of March, as was originally planned, so it's back to the drawing board.

We're told Justin and Hailey initially panicked and started to scramble for another date, but then it dawned on them -- THEY'RE ALREADY MARRIED, so there's no rush.

Our sources say the wedding will not be anytime soon ... they want to properly plan it this time with plenty of warning for guests. We're told they're now thinking they may want to do a destination wedding, knowing that would pare down the guest list considerably.

We know some of the guests Justin and Hailey had invited include Kylie Jenner and Travis Scott, Chris Brown, Drake and Odell Beckham Jr.

4th time's a charm?