Seafile and R2 storage, "date didn't parse successfully"

I am currently experimenting setting up R2 as the storage backend for the file managing and sharing tool Seafile The configuration is easy, but Seafile is unable to write to any R2 bucket. Relevant part from the Seafile log:

2023-10-16 10:25:51 ../common/s3-client.c(949): S3 error status for HEAD: 400.
2023-10-16 10:25:51 ../common/s3-client.c(725): S3 error status for PUT: 400.
2023-10-16 10:25:51 ../common/s3-client.c(726): Request URL:
2023-10-16 10:25:51 ../common/s3-client.c(727): Request headers:
2023-10-16 10:25:51 ../common/s3-client.c(624): Date: Mon, 16 Oct 2023 10:25:51 +0000
2023-10-16 10:25:51 ../common/s3-client.c(624): Authorization: AWS4-HMAC-SHA256 Credential=zzz/20231016/auto/s3/aws4_request,SignedHeaders=host;x-amz-content-sha256,Signature=zzz
2023-10-16 10:25:51 ../common/s3-client.c(624): x-amz-content-sha256: f3f9b62407881ed11c004b4083c1df5ed4167bdd2c791a3f0923ca7dd179b891
2023-10-16 10:25:51 ../common/obj-backend-s3.c(348): Put object 2e59c01c240cc087514acb013e5a787bd7607b77 error 400. Response:
<?xml version="1.0" encoding="UTF-8"?><Error><Code>InvalidArgument</Code><Message>**Invalid Argument: Date provided in &apos;date&apos; header (Mon, 16 Oct 2023 10:25:51 +0000) didn&apos;t parse successfully**</Message></Error>
2023-10-16 10:25:51 repo-mgr.c(7176): Failed to add commit.

It appears that R2 rejects the date header content Mon, 16 Oct 2023 10:25:51 +0000. What’s wrong with this date string?

Seafile claims compatibility with at least OpenStack and Ceph object storage apart from AWS.