我在 docker 容器（操作系统：Ubuntu 18.04.4 LTS）中本地运行 Odoo 13 社区版。我已连接收件服务器 (imap.gmail.com)。现在，每次在预定操作“邮件：Fetchmail 服务”之后出现此错误：
web_1 | 2020-02-07 07:10:29,290 1 INFO odoo_call_center odoo.addons.base.models.ir_cron: Starting job `Mail: Fetchmail Service`.
web_1 | 2020-02-07 07:10:29,318 1 INFO odoo_call_center odoo.addons.fetchmail.models.fetchmail: start checking for new emails on imap server test_gmail_in_IMAP
web_1 | 2020-02-07 07:10:30,880 1 INFO odoo_call_center odoo.addons.fetchmail.models.fetchmail: Fetched 0 email(s) on imap server test_gmail_in_IMAP; 0 succeeded, 0 failed.
db_1 | 2020-02-07 07:10:31.076 UTC [37] ERROR: could not obtain lock on row in relation "ir_cron"
db_1 | 2020-02-07 07:10:31.076 UTC [37] STATEMENT: SELECT *
db_1 | FROM ir_cron
db_1 | WHERE numbercall != 0
db_1 | AND active
db_1 | AND nextcall <= (now() at time zone 'UTC')
db_1 | AND id=8
db_1 | FOR UPDATE NOWAIT
db_1 | 2020-02-07 07:10:31.207 UTC [38] ERROR: could not obtain lock on row in relation "ir_cron"
db_1 | 2020-02-07 07:10:31.207 UTC [38] STATEMENT: SELECT id FROM "ir_cron" WHERE id IN (8) FOR UPDATE NOWAIT
web_1 | 2020-02-07 07:10:31,312 1 INFO odoo_call_center odoo.addons.base.models.ir_cron: Job `Mail: Fetchmail Service` done.
当我手动运行此操作时，没有错误：
web_1 | 2020-02-07 07:36:59,253 1 INFO odoo_call_center werkzeug: 172.18.0.1 - - [07/Feb/2020 07:36:59] "POST /web/dataset/call_kw/ir.attachment/search_read HTTP/1.1" 200 - 5 0.002 0.004
web_1 | 2020-02-07 07:36:59,274 1 INFO odoo_call_center odoo.addons.fetchmail.models.fetchmail: start checking for new emails on imap server test_gmail_in_IMAP
web_1 | 2020-02-07 07:37:00,375 1 INFO odoo_call_center odoo.addons.fetchmail.models.fetchmail: Fetched 0 email(s) on imap server test_gmail_in_IMAP; 0 succeeded, 0 failed.
web_1 | 2020-02-07 07:37:00,755 1 INFO odoo_call_center werkzeug: 172.18.0.1 - - [07/Feb/2020 07:37:00] "POST /web/dataset/call_button HTTP/1.1" 200 - 33 0.026 1.473
web_1 | 2020-02-07 07:37:00,838 1 INFO odoo_call_center werkzeug: 172.18.0.1 - - [07/Feb/2020 07:37:00] "POST /web/dataset/call_kw/ir.cron/read HTTP/1.1" 200 - 60 0.023 0.020
Mail servis 实际工作：我可以接收和发送电子邮件。我将它设置interval_number为 10 分钟，所以它不会太小。设置max_cron_threads = 1instedmax_cron_threads = 2也没有效果。
我是使用 Odoo 和整个编程的新手。我很乐意收到建议。