MeijerG::rarg
An error occurs because zero is not a valid value for the fourth argument in MeijerG in combination with the other arguments used here:
MeijerG[{{2.5}, {1}}, {{}, {1, 1}}, I, 0]This shows valid arguments in MeijerG:
MeijerG[{{2.5}, {1}}, {{}, {1, 1}}, I, 2]