You might not have seen this posting which describes a Thunderbird/Lightning related problem, which has definitely been solved with Thunderbird 60.5.1/Lightning 6.5.2.1 (see https://github.com/nextcloud/server/issues/10134 for some background).
You might not have seen this posting which describes a Thunderbird/Lightning related problem, which has definitely been solved with Thunderbird 60.5.1/Lightning 6.5.2.1 (see https://github.com/nextcloud/server/issues/10134 for some background).