eM Client still decrypt attachment after removing PGP key with error: Encryption has problems.

I have imported my PGP keys in option “Signing and Encryption“. But eM Client had a problem to decrypt emails that have been delivered.
So I have removed my PGP keys and eM Client unfortunately is still trying to decrypt the .pgp attachment with error: Encryption has problems
Is there any way to fix it or disable this PGP function?