(I say this is a note about business, but on second reading, it applies just as easily to any relationship. Duly noted...)
Do not be afraid to admit it when you made a mistake. Don’t grovel or whine, just say “I’m sorry I dropped the ball on that one. Can we move forward?” Because you never know when a mistake can turn around into something good. Miscommunications, when repaired, often create greater understanding in the long run.
I’m speaking from personal experience, of course, but that’s all I can say for now! Hopefully this mistake-turned-good will continue to be good, and I can give details in a few weeks.