sync_client: IOERROR: fetching subscriptions

[Jean Charles Delépine]

Hello,

While replicating one 3.0.9 server to a 3.2.3 server 2 accounts failed to 
synchronise with this error :

OK success
cyrus/sync_client[2745008]: IOERROR: fetching subscriptions for user1
Error from sync_do_user(user1): bailing out!
cyrus/sync_client[2745008]: Error in sync_do_user(user1): bailing out!
> 1601973199>EXIT
<1601973199<OK Finished

Trying to migrate this mailbox on another server (3.0.9) gave a similar 
error :

2020-10-06T10:51:43.556312+02:00 cyrus-3.0.8  cyrus/imap[2714758]: XFER: user 'user1' ->  cyrus-3.2.3
2020-10-06T10:51:43.558342+02:00 cyrus-3.0.8  cyrus/imap[2714758]: XFER: initial sync of user user1
2020-10-06T10:51:43.558575+02:00 cyrus-3.0.8  cyrus/imap[2714758]: USER user1
2020-10-06T10:51:43.933958+02:00 cyrus-3.0.8  cyrus/imap[2714758]: LOCAL_MAILBOX user.user1
2020-10-06T10:51:44.714252+02:00 cyrus-3.0.8  cyrus/imap[2714758]: LOCAL_MAILBOX user.user1.Drafts
[...]
2020-10-06T10:51:44.988079+02:00 cyrus-3.0.8  cyrus/imap[2714758]: LOCAL_MAILBOX user.user1.Trash
2020-10-06T10:51:45.070636+02:00 cyrus-3.0.8  cyrus/imap[2714758]: IOERROR: fetching subscriptions for user1

The user can list his subscriptions and change them :

C: A01 AUTHENTICATE PLAIN ZGQtbGFyaWEAZGQtbGFyaWEARzRsYUZvdWkx                                                                          
S: A01 OK [CAPABILITY IMAP4rev1 LITERAL+ ID ENABLE ACL RIGHTS=kxten QUOTA MAILBOX-REFERRALS NAMESPACE UIDPLUS NO_ATOMIC_RENAME UNSELECT 
CHILDREN MULTIAPPEND BINARY CATENATE CONDSTORE ESEARCH SEARCH=FUZZY SORT SORT=MODSEQ SORT=DISPLAY SORT=UID THREAD=ORDEREDSUBJECT THREAD=
REFERENCES THREAD=REFS ANNOTATEMORE ANNOTATE-EXPERIMENT-1 METADATA LIST-EXTENDED LIST-STATUS LIST-MYRIGHTS LIST-METADATA WITHIN QRESYNC 
SCAN XLIST XMOVE MOVE SPECIAL-USE CREATE-SPECIAL-USE DIGEST=SHA1 X-REPLICATION URLAUTH URLAUTH=BINARY MUPDATE=mupdate://cyrus-mupdate/
LOGINDISABLED COMPRESS=DEFLATE X-QUOTA=STORAGE X-QUOTA=MESSAGE X-QUOTA=X-ANNOTATION-STORAGE X-QUOTA=X-NUM-FOLDERS IDLE] Success (tls
  protection) SESSIONID=<cyrus-3052704-1602066687-1-8472774015412610484>                                                                 
Authenticated.                                                                                                                          
Security strength factor: 256                                                                                                           
. LSUB "*" "*"                                                                                                                          
* LSUB (\HasChildren) "." INBOX                                                                                                         
[...]
* LSUB () "." INBOX.archives.2000-2019.2018
* LSUB () "." INBOX.archives.2000-2019.2019                                                                                             
. OK Completed (0.006 secs)                                                                                                             
. UNSUBSCRIBE INBOX.archives.2000-2019.2019                                                                                             
. OK Completed                                                                                                                          
. LSUB "*" "*"                                                                                                                          
* LSUB (\HasChildren) "." INBOX
[...]
* LSUB () "." INBOX.archives.2000-2019.2018



I don't understand. Where can be the problem ?

Sincerly,
      Jean Charles Delépine