Calibre-Web 500 Error

[2019-04-03 20:40:54,076] ERROR in app: Exception on /series [GET]

Traceback (most recent call last):

  File "/usr/lib/python2.7/site-packages/flask/app.py", line 2292, in wsgi_app

    response = self.full_dispatch_request()

  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1815, in full_dispatch_request

    rv = self.handle_user_exception(e)

  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1718, in handle_user_exception

    reraise(exc_type, exc_value, tb)

  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1813, in full_dispatch_request

    rv = self.dispatch_request()

  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1799, in dispatch_request

    return self.view_functions[rule.endpoint](**req.view_args)

  File "/app/calibre-web/cps/web.py", line 344, in decorated_view

    return login_required(func)(*args, **kwargs)

  File "/usr/lib/python2.7/site-packages/flask_login/utils.py", line 261, in decorated_view

    return func(*args, **kwargs)

  File "/app/calibre-web/cps/web.py", line 1413, in series_list

    .group_by('books_series_link.series').order_by(db.Series.sort).all()

  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 3160, in all

    return list(self)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 3316, in __iter__

    return self._execute_and_instances(context)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 3341, in _execute_and_instances

    result = conn.execute(querycontext.statement, self._params)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 988, in execute

    return meth(self, multiparams, params)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/elements.py", line 287, in _execute_on_connection

    return connection._execute_clauseelement(self, multiparams, params)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1098, in _execute_clauseelement

    else None,

  File "<string>", line 1, in <lambda>

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/elements.py", line 462, in compile

    return self._compiler(dialect, bind=bind, **kw)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/elements.py", line 468, in _compiler

    return dialect.statement_compiler(dialect, self, **kw)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 562, in __init__

    Compiled.__init__(self, dialect, statement, **kwargs)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 319, in __init__

    self.string = self.process(self.statement, **compile_kwargs)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 350, in process

    return obj._compiler_dispatch(self, **kwargs)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 91, in _compiler_dispatch

    return meth(self, **kw)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 2115, in visit_select

    text, select, inner_columns, froms, byfrom, kwargs

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 2219, in _compose_select_body

    text += self.group_by_clause(select, **kwargs)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 2277, in group_by_clause

    group_by = select._group_by_clause._compiler_dispatch(self, **kw)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 104, in _compiler_dispatch

    return meth(self, **kw)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 970, in visit_clauselist

    c._compiler_dispatch(self, **kw) for c in clauselist.clauses

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 968, in <genexpr>

    s

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 970, in <genexpr>

    c._compiler_dispatch(self, **kw) for c in clauselist.clauses

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 104, in _compiler_dispatch

    return meth(self, **kw)

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py", line 772, in visit_textual_label_reference

    "Can't resolve label reference for ORDER BY / GROUP BY.",

  File "/usr/lib/python2.7/site-packages/sqlalchemy/sql/elements.py", line 4501, in _no_text_coercion

    "extra": "%s " % extra if extra else "",

CompileError: Can't resolve label reference for ORDER BY / GROUP BY. Textual SQL expression 'books_series_link.series' should be explicitly declared as text('books_series_link.series')

::ffff:172.17.0.1 - - [2019-04-03 20:40:54] "GET /series HTTP/1.1" 500 412 0.053049