服务器上的 Solr HTTP 错误，HTTP 请求失败

搜索停止工作，在服务器上的日志中是：

Request.CRITICAL: Uncaught PHP Exception Solarium\Exception\HttpException:
"Solr HTTP error: HTTP request failed, Failed to connect to solr port 8983:
Connection refused" at
/var/www/vendor/solarium/solarium/library/Solarium/Core/Client/Adapter/Curl.php
line 195 {"exception":"[object] (Solarium\\Exception\\HttpException(code: 0): 
Solr HTTP error: HTTP request failed, Failed to connect to solr port 8983:
Connection refused at 
/var/www/vendor/solarium/solarium/library/Solarium/Core/Client/Adapter/Curl.php:195)"} []

欢迎任何关于这与什么有关的猜测。

docker-compose.yml：

solr:
        image: solr:latest
        env_file: .env
        ports:
            - 8983:8983
        volumes:
            - solr_volume:/opt/solr/server/solr/mycores
        entrypoint:
            - docker-entrypoint.sh
            - solr-precreate
            - ${SOLR_CORE}

.env：

# Solr
SOLR_HOST=solr
SOLR_PORT=8983
SOLR_PATH=/solr/
SOLR_CORE=election

正在运行的 docker 容器