Import of CSV file fails with "One of the timestamps is not a valid number. Abort"

[amcleodUNH]

I have Chrony files I'm attempting to analyze using PlotJuggler. They are saved as CSV flat files as follows:

Timestamp,Source,Leap_Status,Stratum,RFC_1-3,RFC_5-7,MD_MDR_MDDR_SyncLoop,LocalPoll,RemotePoll,Score,EstimatedLocalError,PeerDelay,PeerDispersion,RootDelay,RootDispersion,RefID,NTPMode,TX_TS,RX_TS
2022-01-03-15:49:10,129.6.15.29,N,1,111,111,1111,4,13,0.00,1.004e+01,2.842e-02,5.700e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:12,129.6.15.28,N,1,111,111,1111,4,13,0.00,1.004e+01,2.371e-02,4.758e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:12,129.6.15.29,N,1,111,111,1111,4,13,0.00,1.004e+01,2.295e-02,4.606e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:14,129.6.15.28,N,1,111,111,1111,4,13,0.00,1.004e+01,2.579e-02,5.174e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:14,129.6.15.29,N,1,111,111,1111,4,13,0.00,1.004e+01,2.514e-02,5.044e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:16,129.6.15.29,N,1,111,111,1111,4,13,0.00,1.004e+01,2.290e-02,4.596e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:28,129.6.15.28,N,1,111,111,1111,4,13,0.15,-1.031e-03,2.616e-02,5.249e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:30,129.6.15.28,N,1,111,111,1111,4,13,0.05,3.458e-04,2.363e-02,4.742e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:42,129.6.15.29,N,1,111,111,1111,4,13,0.00,9.934e-04,2.315e-02,4.647e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:49:47,129.6.15.28,N,1,111,111,1111,4,13,0.00,1.377e-03,2.373e-02,4.763e-05,2.441e-04,4.883e-04,4E495354,4B,D,K
2022-01-03-15:50:15,129.6.15.29,N,1,111,111,1111,4,13,0.17,2.565e-03,2.609e-02,3.206e-06,2.441e-04,4.883e-04,4E495354,4B,D,K

The timestamp formatting of column one has been modified several times, but consistently generated the same failure message. Can anyone see what must be done to reformat the timestamp column for clean import?