when I plug my nokia 3310 it will say not charging with a stop sign.

Hi,

Have you tried a different compatible charger or charging it from a USB port in a computer?

Use a strong light and a magnifying glass to check that there is no debris lodged in the charge port and that all the pins are still there and not bent or broken. If there is any lint etc, then do not use a metal pin or probe to try and clear it. Use a vacuum cleaner to try and suck it out. If it still won’t dislodge then try using a sharpened wooden toothpick to gently prise it out

It the port seems OK and if it still doesn’t charge try replacing the battery and check if it now charges OK.

Search online for Nokia 3310 battery to find suppliers that suit you.