Teensy 4.1 and Arduino Nano SPI communication HELP!!!!!

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I need help with communication between Arduino nano and teensy 4.1. So i have teensy as a SLAVE and arduino as MASTER. I have used SPI_MSTransfer_T4 for teensy
and I used the SLAVE code and for arduino i tried the MASTER code from that library and I also tried normal arduino code but with no succes i got this error on the teensy:

C:\Users\Pc\Documents\Windows file\SPI_MSTransfer_T4-main\examples\SPI_MSTransfer_SLAVE\SPI_MSTransfer_SLAVE.ino:1:
c:\Users\Pc\Documents\Arduino\libraries\SPI_MSTransfer_T4-main/SPI_MSTransfer_T4.tpp: In function 'void spi0_slave_isr()':
c:\Users\Pc\Documents\Arduino\libraries\SPI_MSTransfer_T4-main/SPI_MSTransfer_T4.tpp:7:34: warning: 'this' pointer is null [-Wnonnull]
7 | _SPI0->SPI_MSTransfer_SLAVE_ISR();
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
c:\Users\Pc\Documents\Arduino\libraries\SPI_MSTransfer_T4-main/SPI_MSTransfer_T4.tpp: In function 'void spi1_slave_isr()':
c:\Users\Pc\Documents\Arduino\libraries\SPI_MSTransfer_T4-main/SPI_MSTransfer_T4.tpp:7:34: warning: 'this' pointer is null [-Wnonnull]
7 | _SPI0->SPI_MSTransfer_SLAVE_ISR();
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
c:\Users\Pc\Documents\Arduino\libraries\SPI_MSTransfer_T4-main/SPI_MSTransfer_T4.tpp: In function 'void spi2_slave_isr()':
c:\Users\Pc\Documents\Arduino\libraries\SPI_MSTransfer_T4-main/SPI_MSTransfer_T4.tpp:7:34: warning: 'this' pointer is null [-Wnonnull]

But it still went throught and i got random numbers form 0 to 255.
Any help appreciated.
Also maybe should be at top but is it even possible i mean SPI from arduino to teensy. Where teensy is SLAVE and arduino is MASTER.