I lost a bid. I don't know why. My bid never went through, see screenshot.
https://paste.pics/4646fe285ee77f02fba7bd5c999c643d
There was no reason that it should not have gone through that I know of. Maybe you can find out if there is an error log or something.
I also found that a lot of the help guide links return errors, the advanced bidding links for example.

Hello Carlos,
Thank you for your report. As you hopefully noticed, we jumped on this as soon as you reported it. It looks like the screenshot disappeared, which we haven't seen before. Can you recall if you have purchased from this seller previously?
We investigated to see what we encountered when we placed your bids. We placed the same snipes from two locations and each returned the same result. Unfortunately, there are some circumstances we can't catch until we place the bid. Sellers can set fairly strict preferences; one of them is to allow only one purchase per eBay ID.
Virtually every situation we encounter that blocks a bid is listed here:
https://bidslammer.com/help/bulletproof/
We welcome any follow-up comments or questions you may have.