I just didn’t clean my beer lines from brew pot to my plate chiller
Using the correct terminology can prevent a lot of misunderstandings and misdirections, while it helps pinpoint responses.
Wort becomes
beer after you pitch yeast. So what's in and what comes out of your kettle is
wort. What goes into your fermenter is
wort. Until after you pitch the yeast, then it's
beer.
Beer lines are typical lines that contain
beer, as in a serving system. Apparently, you meant wort lines, or wort hoses.
The 'hot side' of the brewing process is a lot less finicky about cleanliness and sanitation since heat itself is a sanitation process, it kills microbes. Smooth surfaces are usually fine after being rinsed/washed off, the heat will take care of those in the next brew. But... in tighter, shielded areas, microbes could remain, hiding in crevices, surviving the heat, and grow in whatever wort remains trapped, causing infection havoc later on. So inspecting and thorough cleaning of those critical areas is paramount.
Once chilled, wort is 'waiting' to be inoculated by whatever is around. Dirty equipment such as vessels, tubing, spigots, mesh bags, etc. are infection hazards to wort and beer. That's why everything on the 'cold side' of the brewing process that touches your wort or beer needs to be a) clean and b) sanitized properly to prevent infection.
Rules of thumb:
Cleaning and sanitizing are 2 different processes.
Things can't be sanitized unless they are clean first, e.g., you can't sanitize dirt.