Он, должно быть, не сумел передать

Он, должно быть, не сумел передать им нашу записку, и они, возможно, ждут нас.

Results (English) 1:

He must have failed to convey to them our note, and they may be waiting for us.

Results (English) 2:

He must have failed to convey to them our note, and they may await us.

Results (English) 3:

It should be, has not been able to convey to them our note, and they may be, are waiting for us.