Dell Precision I9 RAM upgrade

Dear forum,

I own a Precision 5820 workstation with 64 GB of RAM (4 x 16 GB, DDR4 UDIMM RAM, 3200 MHz) no ECC). It´s running an Intel Core i9 10980 XE CPU. RAM is running on banks 1-4

I recently bought 2 x 32 GB Crucial Pro RAM sticks ( DDR4-3200 MHz UDIMM CL22) and installed them on banks 5 and 6. The upgrade is for a high end video post production project.

System did not boot up, no error messages, no beeping.

Removed the RAM, system boots up, all okay

Now my question:

1. Is this the wrong type of RAM? I know it would be for a Xeon, but I believed an I9 should be okay
2. Does the RAM need to be the same number of GB across all banks? So I would need to get 16 GB RAM sticks.
3. Should it work and the RAM might just be broken? In this case I would return it to the seller and get a replacement

Thank you very much for your support in advance.