non-descript error when polling xkcd fails about xkcd HOT 5 CLOSED

$ docker-compose logs maubot | grep <bot-username> | grep -v crypto
[2023-02-16 17:20:37,725] [[email protected].@<bot-username>:domain.com] Enabling DecryptionDispatcher
[2023-02-16 17:20:37,725] [[email protected].<instance-id>] Plugin instance dependencies loaded
[2023-02-16 17:20:37,727] [[email protected].@<bot-username>:domain.com] req #1: GET https://matrix.domain.com/_matrix/client/versions None
[2023-02-16 17:20:37,835] [[email protected].@<bot-username>:domain.com] req #1 (/versions) completed in 108.0ms with status 200
[2023-02-16 17:20:37,836] [[email protected].@<bot-username>:domain.com] req #3: GET https://matrix.domain.com/_matrix/client/v3/account/whoami None
[2023-02-16 17:20:37,847] [[email protected].@<bot-username>:domain.com] req #3 (/v3/account/whoami) completed in 11.0ms with status 200
[2023-02-16 17:20:37,848] [[email protected].@<bot-username>:domain.com] req #6: GET https://matrix.domain.com/_matrix/client/v3/profile/%40<bot-username>%3Adomain.com/displayname None
[2023-02-16 17:20:37,856] [[email protected].@<bot-username>:domain.com] req #6 (/v3/profile/%40<bot-username>%3Adomain.com/displayname) completed in 7.9ms with status 200
[2023-02-16 17:20:37,856] [[email protected].@<bot-username>:domain.com] req #8: GET https://matrix.domain.com/_matrix/client/v3/profile/%40<bot-username>%3Adomain.com/avatar_url None
[2023-02-16 17:20:37,862] [[email protected].@<bot-username>:domain.com] req #8 (/v3/profile/%40<bot-username>%3Adomain.com/avatar_url) completed in 6.2ms with status 200
[2023-02-16 17:20:37,863] [[email protected].@<bot-username>:domain.com] Enabling end-to-end encryption support
[2023-02-16 17:20:37,871] [[email protected].@<bot-username>:domain.com] req #11: GET https://matrix.domain.com/_matrix/client/v3/profile/%40<bot-username>%3Adomain.com None
[2023-02-16 17:20:37,871] [[email protected].@<bot-username>:domain.com] Starting syncing
[2023-02-16 17:20:37,976] [[email protected].@<bot-username>:domain.com] req #11 (/v3/profile/%40<bot-username>%3Adomain.com) completed in 105.2ms with status 200
[2023-02-16 17:20:37,976] [[email protected].@<bot-username>:domain.com] Client started, starting plugin instances...
[2023-02-16 17:20:38,104] [[email protected].<instance-id>] Started instance of xyz.maubot.xkcd v1.1.2 with user @<bot-username>:domain.com
[2023-02-16 17:20:38,104] [[email protected].<instance-id>] Polling started
[2023-02-16 17:20:38,107] [[email protected].<instance-id>] Plugin instance dependencies loaded
[2023-02-16 17:20:38,270] [[email protected].<instance-id>] Failed to poll xkcd
[2023-02-16 19:40:49,024] [[email protected].@<bot-username>:domain.com] req #656: POST https://matrix.domain.com/_matrix/client/v3/keys/query {"timeout": 10000, "device_keys": {"@<user>:domain.com": []}}
[2023-02-16 19:40:49,086] [[email protected].@<bot-username>:domain.com] req #656 (/v3/keys/query) completed in 61.4ms with status 200
[2023-02-16 19:41:54,640] [[email protected].@<bot-username>:domain.com] req #669: POST https://matrix.domain.com/_matrix/client/v3/keys/query {"timeout": 10000, "device_keys": {"@<other-user>:domain.com": []}}
...