1. Check the tuning pegs: Make sure that the E string tuning peg is properly tightened and the string is wound evenly. If the peg is loose, tighten it by turning it clockwise until the string is at the proper pitch.
2. Check the string tension: The E string may be too loose or too tight. Try adjusting the tension by turning the tuning peg slightly clockwise to tighten the string or counterclockwise to loosen it. Make small adjustments and listen to the pitch until the string is in tune.
3. Check the bridge: The E string may not be properly seated in the bridge. Check to make sure that the string is positioned correctly in the slot and that the saddle is properly adjusted. If the saddle is too high or too low, it can affect the intonation of the string.
4. Check the nut: The E string may be caught on the nut, which can cause it to sound out of tune. Check to make sure that the string is properly seated in the nut slot and that there are no obstructions preventing the string from vibrating freely.
5. Check the frets: The E string may be buzzing against a fret, which can cause it to sound out of tune. Check to make sure that the frets are level and that the string is not touching any of them. If a fret is too high, you may need to have it filed down by a guitar technician.
6. Check the intonation: The intonation of your guitar may need to be adjusted. This involves adjusting the length of the strings so that they are in tune at every fret. You can check the intonation by playing each note on the E string and comparing it to the corresponding note on the tuner. If the notes are out of tune, you may need to adjust the intonation screws on the bridge.
If you are unable to resolve the issue by following these steps, it is recommended that you take your guitar to a qualified guitar technician for further inspection and adjustment.