MA01
Alert: If you do not agree with what we approved for these services, you may appeal our decision. To make sure that we are fair to you, we require another individual that did not process your initial claim to conduct the appeal. However, in order to be eligible for an appeal, you must write to us within 120 days of the date you received this notice, unless you have a good reason for being late.
We can appeal any of Medicare rejection but it should be with 120 days from the EOB date.
MA07
Alert: The claim information has also been forwarded to Medicaid for review.
Medicare automatically forward the primary EOB to secondary insurance so there is no need to send a secondary claim.

MA09
Claim submitted as unassigned but processed as assigned. You agreed to accept

assignment for all claims.
It says that all the claims will be considered as accept assignment claim even we uncheck the box 25.
MA15
Alert: Your claim has been separated to expedite handling. You will receive a separate notice for the other services reported.
This codes saying that our claims has been seperated for easy processing so Medicare will pay or deny other claims.

MA48
Missing/incomplete/invalid name or address of responsible party or primary payer.
For all the secondary claims, we should include primary insurance details.
MA60
Missing/incomplete/invalid patient relationship to insured.
For Medicare the relationship always self, Check this info in your claim and rebill.

MA61
Missing/incomplete/invalid social security number or health insurance claim number.
Check the id.

MA63
Missing/incomplete/invalid principal diagnosis.
Check the primary Dx.

MA67
Correction to a prior claim.
Its is a correction of previously paid claim and for clear picture see the previous EOB.

MA83
Did not indicate whether we are the primary or secondary payer.
All the claim should be indicated as primary or secondary. Top of the CMS -1500
MA89
Missing/incomplete/invalid patient’s relationship to the insured for the primary payer.
Again the relationship should be Self.

MA90
Missing/incomplete/invalid employment status code for the primary insured.

MA112
Missing/incomplete/invalid group practice information.
Check the Provider ID. BOX 33.

Links are simillar denials and solutions