Decryption troubles

[Roland Siemons]

Dear GNUPGs,

I have strange troubles with my key.

I DO can decrypt encrypted files that other people prepared for me,
using the public part of my key for encryption.

I canNOT decrypt files that were made by myself, using the same key. I
receive this error message:
"The GPGME library returned an unexpected error at
gpafiledecryptop.c:540. The error was: No secret key."

I am using GPA with GnuPG 2.2.10.

Please advise!

-- 
Roland Siemons
Haaksbergerstraat 205
ENSCHEDE

t: O645616734