Here are some logs, maybe related to my problem.
Aug 23 20:43:57 Panic: doveadm(mail@example.com)<1355655><rdvZDu0fBWOHrxQAuroN3Q>: file dsync-brain-mailbox.c: line 883 (dsync_brain_slave_recv_mailbox): assertion failed: (memcmp(dsync_box->mailbox_guid, local_dsync_box.mailbox_guid, sizeof(dsync_box->mailbox_guid)) == 0) Aug 23 20:43:57 Error: doveadm(mail@example.com)<1355655><rdvZDu0fBWOHrxQAuroN3Q>: Raw backtrace: /usr/local/lib/dovecot/libdovecot.so.0(backtrace_append+0x42) [0x7f3c4c30e562] -> /usr/local/lib/dovecot/libdovecot.so.0(backtrace_get+0x1e) [0x7f3c4c30e67e] -> /usr/local/lib/dovecot/libdovecot.so.0(+0x1022db) [0x7f3c4c31b2db] -> /usr/local/lib/dovecot/libdovecot.so.0(+0x102371) [0x7f3c4c31b371] -> /usr/local/lib/dovecot/libdovecot.so.0(+0x55589) [0x7f3c4c26e589] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f680618] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f67de26] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f67e483] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f68fe1f] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x69) [0x7f3c4c331509] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x132) [0x7f3c4c332bf2] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x50) [0x7f3c4c3315b0] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_run+0x40) [0x7f3c4c331770] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f662335] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f664ba5] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f665c5a] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f675bb1] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f679ffa] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x69) [0x7f3c4c331509] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x132) [0x7f3c4c332bf2] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x50) [0x7f3c4c3315b0] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_run+0x40) [0x7f3c4c331770] -> /usr/local/lib/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7f3c4c2a4333] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f655162] -> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xea) [0x7f3c4bf30d0a] -> dovecot/doveadm-server 172.17.1.12 mail@example.com slave_recv_mailbox [0x56099f6551ea]