Short answer. Nine grounds, mostly procedural lapses: missed deadlines for the notice of appeal or record on appeal, unpaid docket fees, defective briefs, failure to correct the record when ordered, missing the preliminary conference without justifiable cause, or appealing an order that is simply not appealable.
What the law says
An appeal may be dismissed by the Court of Appeals, on its own motion or on that of the appellee, on the following grounds: (a) Failure of the record on appeal to show on its face that the appeal was taken within the period fixed by these Rules; (b) Failure to file the notice of appeal or the record on appeal within the period prescribed by these Rules; (c) Failure of the appellant to pay the docket and other lawful fees as provided in section 5 of Rule 40 and section 4 of Rule 41
Rule 50, Section 1 — Grounds for dismissal of appeal. Read the full provision →
The court can act on its own, not only on a motion
Dismissal under this rule can happen on the Court of Appeals' own motion or on that of the appellee. The appellant does not necessarily get advance warning triggered only by the other side's initiative — the court itself can raise and act on these grounds without waiting for the appellee to move first, which makes strict compliance the appellant's own responsibility throughout.
Timing and fee failures are the most common triggers
Several grounds are purely about deadlines and payment: the record on appeal failing to show on its face that the appeal was taken within the period fixed, failure to file the notice of appeal or the record on appeal within the prescribed period, and failure to pay the docket and other lawful fees. These are the most mechanical grounds, and also the easiest to avoid with careful attention to deadlines and requirements.
Brief and record defects can also be fatal
Beyond timing, the rule reaches the substance of the appellate filings: unauthorized alterations, omissions or additions in the approved record on appeal; failing to serve and file the required number of copies of the brief within the time allowed; and the absence of specific assignment of errors or required page references in the appellant's brief. A brief that does not follow the required form can be dismissed just as readily as one that is simply late.
Conduct during the appeal, and the nature of the order itself, matter too
The remaining grounds cover an appellant's failure to take necessary steps to correct or complete the record within a court-ordered deadline, failure to appear at the preliminary conference or comply with the court's orders and directives without justifiable cause, and — separately from anything the appellant did or failed to do — the simple fact that the order or judgment appealed from is not appealable in the first place, which no amount of procedural diligence by the appellant can cure.