No more bookings permitted. Reservation has reached maximum.

it is incorrect.
RT CLS SUSPENDED has nothing to do with waiting lists or bookings. it is generally a temporary restriction on bookings for the said train on that particular day in the said class.

RT CLS SUSPNDED
This appears -- when the waiting list for any class had reached the maximum limit fixed and no further wait listed tickets can be issued.
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It means on the particular date for which you are checking the availability of the route and class -- the booking is suspended.