EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors; Airspace Structure
Indy Center told us direct to KLINE fix somewhere after we passed PXV; then [a] few minutes later inquired us if we were flying to the fix. We then figured out center was referring to 'KLYNE'. Because there were two similar sounding fixes; there were some confusion with the direct to. We proceeded to the new assigned fix 'KLYNE' and continued the flight.During pre-flight; my First Officer (FO) was receiving ATC clearance; and we were given a reroute KDFW to ZZZ. I was listening from the speakers and copied the new route on the flight release. I had copied it on the paper release as the controller spelled out the fixes. The FO copied it just the same way as 'KLINE' was spelled out to us on his notepad. Shortly after we input the flight plan to the FMS; and found out that Q29.WWSHR returned an error WAYPOINT NOT FOUND from the FMS. The EFB JeppFD-Pro gave 'Q29 Not Connected to WWSHR' error. So FO called ATC again to verify our route. The [new] route was sent via ACARS to dispatch to check with fuel requirements. Rename one of the 'KLYNE' or 'KLINE' fixes should clear confusion with ATC and pilots. The fixes are about 50nm apart on the same ATC center. That way; there will be no 2 fixes that can pronounce the same.
[Report narrative contained no additional information.]
ERJ-175 flight crew reported they deviated from cleared track after confusing the similar fixes KLINE and KLYNE.