solaris user, group match but permission denied

Question

I have a problem on solaris.... I login with userA, and when I execute the file, it just shows permission denied. I've checked everything... i've no idea. pls help.. Here's the background and what I need to do..

cat /etc/group | grep groupA
groupA::10:
cat /etc/group | grep groupB
groupB::65535:userA

id
uid=1010(userA) gid=10(groupA)
groups
groupA groupB

My user name and group matches in the directory..

drwxr-xr-x   4 userA    GroupA         34 Apr 30 11:29 .

but when I execute the code with file, it shows permission denied.

 ls -al ./mail_udcsc_rpt.ksh
-rwxr-xr-x   1 userA    groupA       1654 Dec  4  2020 ./mail_test_rpt.ksh
 ./mail_test_rpt.ksh
permission denied
permission denied

Is my setting goes wrong and how to fix it??

please help... thanks a lot.