Here it is the input text - ALRISALAA 0000000000PAY
{1:F01AJEAXXX4428502116}{2:O1990927231231JEAXXX44280581192312310927N}{3:{108:BESS21789599}}{4:
:20:SBI231228000220
:21:599FTIG233620005
:79:WE ACKNOWLEDGE .
5933620005 DATED /28/2023 .WE ARE
CURRENTLY INVESTIGATING THE INQUIRY AND WILL
REVERT VERY SOON.
KINDLY QUOTE OUR REFERENCE I231228000220 IN
FIELD 21 OF ALL YOUR FUTURE CORRESPONDENCE
RELATING TO THIS CASE.
THANKS AND KIND REGARDS
PAYMENTS OPERATION TEAM
HEAD OFFICE
-}{5:{CHK:B3473524E031}}
I tried regex code but its not working (?<=20:).*(?<=21:)