An excuse works once, maybe twice. After that people stop hearing reasons and start hearing a pattern.

Reasons are received individually at first and collectively after that. By the third time, people stop evaluating whether this particular explanation is true and start noticing how often explanations appear, which is a different and much less forgiving kind of judgment. Most of the reasons are probably real, and that does not change what is being heard.

When you are about to explain again, try stating just the fact and what you will do. Then shorten what you promise, so the next report is about a delivery rather than a reason.