My beer is infected

This is my first batch

It was a kit that was supposed to be a brown ale.

It stArted out fine. Fermented fine. There was some trub and yeast taste after fermentation but it basically tasted like a brown ale.

Everything was over sanitized with star san. I filled up the bottling bucket with it and dipped everything in the star san.

I then racked the beer into the bottling bucket with an auto siphon. There was air pockets in the siphon where the hose wouldn't seal tight.

I transferred it into the bottles after using priming sugar......after two weeks I checked it. It was fine.......carbonated fine and tasted ok. Not great but ok.

One week later the beer was sour......all of it. 3 weeks later it was undrinkable sour.

Any ideas.....

What yeast did you use? Also, how did you sanitize your bottles and bottle caps? Did you boil the priming sugar, and if so, for how long?

Did you sanitize the auto siphon and hose? When you say dip into star San, how long was it covered with starsan?

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+1 on all the above.

Definitely a cleaning / sanitation issue.
You can't sanitize unless it's clean. How did you clean those bottles?

Make sure you take your spigot on bottling bucket, auto siphon and bottling wand completely apart when sanitizing. A lot of people do not realize that spigots and bottling wands come apart (plastic ones anyway) - they do. These are key places where bad things can hide.

Get a smaller diameter tube that fits snug with auto siphon and bottling wand.

+1 to boiling priming sugar in some water and adding as a "syrup".

+1 in regard to sanitizing of bottles and caps.

Make sure everything is "clean" before it is "sanitized."

Your issue is probably not the bottles or the caps. They wouldn't all be sour in that case, instead you would see the occasional gusher or otherwise bad bottle while most would be fine.

The bottling bucket and autosiphon and tubing are good places to check but I don't think you can rule out earlier steps in the process. I think you are saying it tasted ok going into the bottling bucket. I am not sure that really means anything. Wild yeast or bacteria could have contaminated the beer very early on and grown slowly and only recently hit your flavor threshold.