Gmail error rsa key

Hi,

As a test I tryed to send the current waether to my personal account on gmail.
The following error occurs:

5 Sep 15:26:35 - [error] [e-mail:my_account@gmail.com] Error: 1996451840:error:0607907F:digital envelope routines:EVP_PKEY_get1_RSA:expecting an rsa key:p_lib.c:279:

No idea what this means.
Cannot find any help at Google. Nor where to find a rsa key in my gmail account.

Anyone a idea ?

Thanks in advance,
René.