Share algorithm with username gives error "Cannot find algorithmId"

Hi,

I am trying to share my algorithm with a specific username, but I get the following error:

I right clicked my indicator, pressed export and put in the username to share it with. Do you know what this error means? My algorithm uses Full Access rights. If I share it with “Access for any user”, it does generate a .algo file: 

There are no build errors. I do make use of referenced indicators, resources (for a png image), Files IO and multi timeframe analyses, but everything works fine when I just build and use it. Unfortunately I can't share the code here, but I hope you could still help me find where to look for the error.

Thanks in advance,

Rico