Series::icm
An error occurs because series expansions around different expansion points cannot be added together:
Series[Sin[x], {x, 1, 2}] + Series[Cos[x], {x, 2, 2}]This shows addition of series expansions with the same expansion point:
Series[Sin[x], {x, 1, 2}] + Series[Cos[x], {x, 1, 2}]