▼テンプレート
[EC-CUBE] 4.0.2
[レンタルサーバ] さくらインターネット VPS　サーバ
[OS] linux
[PHP] PHP: 7.2.18
[データベース] MySQL 5.5.64-MariaDB
[WEBサーバ] Apahce
[導入プラグインの有無] なし
[カスタマイズの有無] なし（テンプレートのみ編集）
[現象]

オーナーズストアからプラグインを導入しようとすると複数回繰り返しても
システムエラーが表示され導入できない。
手動インストールでは問題なく導入が可能。

エラー確認後新規インストールした別環境でも再現


エラーログには下記がでています。

admin.ERROR [mgsocqq9a33g23ub5omblun2hv] [0a84fca] [1] [Eccube\Log\Logger:log:64] - In JsonFile.php line 300: "https://package-api.ec-cube.net/packages.json" does not contain valid JSON Parse error on line 1: ^ Expected one of: 'STRING', 'NUMBER', 'NULL', 'TRUE', 'FALSE', '{', '[' show [--all] [-i|--installed] [-p|--platform] [-a|--available] [-s|--self] [-N|--name-only] [-P|--path] [-t|--tree] [-l|--latest] [-o|--outdated] [--ignore IGNORE] [-m|--minor-only] [-D|--direct] [--strict] [-f|--format FORMAT] [--] [] [] [] [GET, /ecadmin/store/plugin/api/install/1723/confirm,
admin.INFO [mgsocqq9a33g23ub5omblun2hv] [0a84fca] [1] [Eccube\Log\Logger:log:64] - {"command":"config","setting-key":"repositories.eccube","setting-value":["{"type":"composer","url":"https:\/\/package-api.ec-cube.net","options":{"http":{"header":["X-ECCUBE-KEY: ************"]}}}"],"--working-dir":"/html","--no-ansi":true} [GET, /ecadmin/store/plugin/api/install/1723/confirm,
admin.INFO [mgsocqq9a33g23ub5omblun2hv] [0a84fca] [1] [Eccube\Log\Logger:log:64] - http get_info {"url":"https://package-api.ec-cube.net/plugin/1723","content_type":"application/json;charset=UTF-8","http_code":200,"header_size":413,"request_size":192,"filetime":-1,"ssl_verify_result":0,"redirect_count":0,"total_time":0.43831699999999996,"namelookup_time":0.001292,"connect_time":0.002124,"pretransfer_time":0.082419,"size_upload":0,"size_download":989,"speed_download":2256,"speed_upload":0,"download_content_length":-1,"upload_content_length":0,"starttransfer_time":0.438229,"redirect_time":0,"redirect_url":"","primary_ip":"133.242.233.183","certinfo":[],"message":""} [GET, /ecadmin/store/plugin/api/install/1723/confirm,