Help for memory expansion Supermicro X11SSM-F

[2space]

Hello community,
I have been trying to buy 2 more 16GB RAM expansions for my Supermicro X11SSM-F for quite some time. Currently 2x M391A2K43BB1 CL15 2133 are installed. Three attempts with different RAM bars that match the specs, the board already acknowledged with "unsupported".
Do you have a tip where I can buy suitable RAM in Germany or Europe? Am really desperate :(

thx 2space

 

[NugentS]

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[Etorix]

It should not be difficult to find DDR4 UDIMM (Unbuffered). Just make sure not to end up with RDIMM (Registered) when looking for ECC.