How to fix the error: Tx Calibration: MCU error 4 (SXT tune failed)

I did the LimeQuickTest with two different Gatewares:

en1gma@M4800:~$ LimeQuickTest
[ TESTING STARTED ]
->Start time: Wed Oct 14 17:03:32 2020

->Device: LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D3BD0C4F0CDFF, HW=1, GW=1.28
Serial Number: 1D3BD0C4F0CDFF
Chip temperature: 45 C

[ Clock Network Test ]
->REF clock test
Test results: 2563; 15760; 28957 - PASSED
->VCTCXO test
Results : 6710985 (min); 6711150 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 03 10 12 03 10 02
->FPGA EEPROM Test PASSED

[ LMS7002M Test ]
->Perform Registers Test
->External Reset line test
Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
Reg 0x20: value after reset 0x0FFFF
->LMS7002M Test PASSED

[ RF Loopback Test ]
->Configure LMS
->Run Tests (TX_2 → LNA_W):
CH0 (SXR=1000.0MHz, SXT=1005.0MHz): Result:(-28.6 dBFS, 5.00 MHz) - FAILED
->Run Tests (TX_1 → LNA_H):
CH0 (SXR=2100.0MHz, SXT=2105.0MHz): Result:(-11.7 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 2.47 seconds

en1gma@M4800:~$ LimeQuickTest
[ TESTING STARTED ]
->Start time: Wed Oct 14 17:05:24 2020

->Device: LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D3BD0C4F0CDFF, HW=1, GW=1.30
Serial Number: 1D3BD0C4F0CDFF
Chip temperature: 45 C

[ Clock Network Test ]
->REF clock test
Test results: 2318; 15515; 28712 - PASSED
->VCTCXO test
Results : 6710985 (min); 6711151 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 03 10 12 03 10 02
->FPGA EEPROM Test PASSED

[ LMS7002M Test ]
->Perform Registers Test
->External Reset line test
Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
Reg 0x20: value after reset 0x0FFFF
->LMS7002M Test PASSED

[ RF Loopback Test ]
->Configure LMS
->Run Tests (TX_2 → LNA_W):
CH0 (SXR=1000.0MHz, SXT=1005.0MHz): Result:(-28.7 dBFS, 5.00 MHz) - FAILED
->Run Tests (TX_1 → LNA_H):
CH0 (SXR=2100.0MHz, SXT=2105.0MHz): Result:(-11.7 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 2.45 seconds

en1gma@M4800:~$