Cannot open received SMIME mail

Cannot open received SMIME mail

Hello,

I received a SMIME encrypted mail, which I don't know how to open. I'm on the free plan, and I am aware that SMIME encryption is available for the premium plan. Is it true that I cannot read a SMIME encrypted mail that was sent to me if I'm only on the free plan? I tried Googling around, and checking this forum but noone seemed to have had this issue.

Regards,
Rasmus