$re = '/^(?:[^\{]*[\{]){2}\s(?<ReadablePayload>[^\{]*)[\}]\S\s[^\{]*[\{]\s([^\}]*[\}])/s';
$str = '2019-02-08 00:54:43 [TRACE] Malformed message {
[TRACE] Readable Payload { UNH+20038142932000+AIRRQT:15:2:1A+cepSwzsAXFw=800\'ORG+1A:MUC+1234567:NCE1A0950+++T\'BLK+152+RF++000+0000000000+1A:1290861+001:001\'AMD++07:00000000::07FEB++1A:1290861+1A:1290861+MUC:1A: +00:01+++AMSSG34AA:57211534:02+++++++++AMSSG34AA:57211534\'AVC+IBERIA+IB:0755\'BIN+TRFP\'CSC+7906:/++9993WSSU\'DAT+180130+190207+190207\'HAS+000+000:X:OPO+XXX+MAD+XXX+XX:XXXXX:X:X: : : : +XXXX++0\'HAS+000+000:X:MAD+XXX+PMI+XXX+XX:XXXXX:X:X: : : : +XXXX++0\'HAS+000+000:X:PMI+XXX+MAD+XXX+XX:XXXXX:X:X: : : : +XXXX++0\'HAS+000+000:X:MAD+XXX+OPO+XXX+XX:XXXXX:X:X: : : : +XXXX++0\'RFD+L+30JAN18++EUR:88.00:88.00:0.00++XT:48.90:48.90\'KFL\'KRF+ +Q:EUR:3.47:PT: *Q:EUR:10.09:YP: *Q:EUR:25.92:JD: *Q:EUR:7.69:QV: *Q:EUR:1.73:OG: \'ING\'INM+001+01:SANTOS/CARLA MS\'TTN+E+075+5169861484\'EQN+1\'CPN+1*2*3*4\'REF+075-5169861484+07FEB19\'END+X\'UNT+23+1\' },
[TRACE] Reason { Mandatory element is missing.
[TRACE] Error at <src/CBRSegmentDecoders.cpp:21405
[TRACE] Error in segment CSC 06 1 1A TKA in element #2.
[TRACE] ------
[TRACE] Error at <src/CBRMessageDecoders.cpp:121
[TRACE] Error in group Group id: _294728_G_CBR in element #3.
[TRACE] ------
[TRACE] Decoding error in message AIRRQT 15 2 1A PNR in element #4 at character 236 of the buffer, using charset B
[TRACE] Converted segments: ORG - BLK - AMD - AVC - BIN -
[TRACE] Cannot convert CSC from here==>+9993WSSU\'Last segment correctly processed: CSC+7906:/++9993WSSU\'
[TRACE] },
[TRACE] Rejection type { T },
[TRACE] Current line { 251590 },
[TRACE] }';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php