Subscription disappears

We set up an SQL Server 2012 Replication:

+ merge replication

+ push Subscriber (notebooks)

+ retention period 14-days

After some days (less then 14 days) one of the subscriber (notebook) can't replicate anymore. A review showed the following:
The subscription on the notebook has disappeared. An error message regarding this issue can't be found in the log.

We set up the replicate again and set the retention expiration (setting publication) up to 90-days. Deactivating the cleanup jobs regarding subscriber and distribution and testing again.
Result: The replication works fine for a few days. After a certain time (a few days) the subscription on the notebook has dissapeared again.

Maybe someone has a hint? Which other influences (except expiration time and cleanupjobs) are responsible for deleting a subscriber on the Notebook-side.



Thanks in advance (and please excuse my bad English)

Udo