A paper we submitted was rejected without a review because of journal scope issues. After the rejection, I decided to send the same manuscript content (changed formats only according to the journal's guidelines) to another journal where I believe it fits. However, I missed informing other co-authors about the rejection as I presumed it is unnecessary because I am submitting the same version of the MS and we are not particular of the journal and its metrics as long as it is fitting. I experienced the same thing before where the primary and corresponding author did not inform us of the rejection rather send it to another journal without our consent (for me that time it was fine). However, this time one of the co-authors scolded me because of the actions I made and I realised it was wrong. Any advice on how will I handle and respond to this?
You should apologize and admit you were wrong. Don't try to defend your actions. It is a head-slapping error. Send the apology to everyone. Offer to immediately withdraw the submission if anyone desires it. Ask for advice going forward. That should cover it.
All authors need to be on the same page for actions on their work.
You should apologize, but even more importantly, you should understand why it was a mistake, and show that you understand why, so that your coauthors know that you will not make the same mistake in the future.
if various authors of a rejected article resubmit it separately to a distinct journal without coordinating with the other authors, there will be parallel submissions of the same work, potentially to distinct journals (which is not allowed in the rules of most journals), or even several times to the same journal (which is just plain waste of the editor time).
If it was merely a lack of respect of the etiquette of this kind of situation, it would be unreasonable to expect you to "simply" know it. In this case however, it is more like good sense, so humbly apologize and promise to think more symmetrically in the future (not just for this particular situation, for any situation involving collaboration with peers), and hope that you convince them... :)