FET canceled due to a yeast infection (vaginal candidiasis)

My fresh embryo transfer was canceled two days before the procedure due to a yeast infection (vaginal candidiasis), and I’m wondering why this infection may have occurred. I haven’t had sexual intercourse or done anything specific that I believe could have caused it.
What steps should I take to prepare for the next FET and prevent future infections?
For context, I am 36 years old and have one endometrioma measuring 28mm. My first egg retrieval was canceled due to early ovulation. During my second retrieval, I got 4 eggs, resulting in 2 embryos. Both embryos underwent PGT and are normal.
Thank you for your guidance.