Speak of fatigue without accusation
You should avoid accusing people of a lack of motivation. The
team may be discouraged, weary, anxious, or simply needing a break.
Calling them demotivated is equivalent to saying that they
lack interest and engagement -- and if this is the case, then
these are more likely to be results than causes.
Get difficulties and discouragements into the open
If you want to get something back on track, it helps to
understand what's derailing it. Having each person formulate what blocks
him or holds him back (without seeking to justify yourself or
to respond immediately) allows possible grievances and
frustrations to be put into the open: a first step towards then finding
how to change the situation.
Present an initial step forward
A manager does not have the solution to every problem, right
away and all by himself! Likewise, looking at dysfunctions and hearing
people's difficulties does not require you immediately to
respond. The most important thing: take the points raised by the
team truly into consideration, and then propose a first initiative to
move forward. An initial step, simple and realistic,
which emphasizes that we are going to act, even if we do not yet
know the solution.