TYPO3 Core

Creating a sitemap with TYPO3 9 EXT:seo such as in following example results in Google Search console not fetching any URLs because of "General HTTP Error":
https://www.aemka.de/sitemap.xml

PageTypeSuffix part of siteconfig:

  PageTypeSuffix:
    type: PageType
    default: .html
    suffix: .html
    index: 'index'
    map:
      .html: 0
      sitemap.xml: 1533906435

TS part for records in sitemap:

plugin.tx_seo.config {
    xmlSitemap {
        sitemaps {
            news {
                provider = TYPO3\CMS\Seo\XmlSitemap\RecordsXmlSitemapDataProvider
                config {
                    table = tx_example_domain_model_news
                    sortField = title
                    lastModifiedField = tstamp
                    pid = 123
                    recursive = 0
                    url {
                        pageId = 123
                        fieldToParameterMap {
                            uid = tx_example_example[news]=
                        }
                        useCacheHash = 1
                    }
                }
            }
            projects {
                provider = TYPO3\CMS\Seo\XmlSitemap\RecordsXmlSitemapDataProvider
                config {
                    table = tx_example_domain_model_project
                    sortField = title
                    lastModifiedField = tstamp
                    pid = 123
                    recursive = 0
                    url {
                        pageId = 123
                        fieldToParameterMap {
                            uid = tx_example_example[project]=
                        }
                        useCacheHash = 1
                    }
                }
            }
        }
    }
}

See attached screenshot from google search console.