Changing Your Default Timezone:

The default time zone setting that is displayed in the Preferences>Global folder is used to localize the time for received messages and calendar activities in the standard web client.

1) Log in to your cPanel

2) Click on the File Manager icon

3) Click on Setings which you will find at the top right corner.

4) Click on the dropdown and Document Root for your domain name.

5) Set the Show Hidden Files

6) Click the Go button

7) Look for the .htaccess file and right-click on it

8) Click on the Edit option

9) Find and click the Edit button in the lower right corner to continue to the editor.

10) Now In this example, we are setting the timezone to Eastern Standard Time.

#Adjust default time zone
SetEnv TZ America/Washington

11) Click Save Changes button to save your new htaccess configuration.

                                                Or

If htaccess can’t solve your problem, add this code to your PHP

<?php

putenv(“TZ=Europe/Istanbul”);
?>

Also read,

Full List of Time Zone

AD Europe/Andorra

AE Asia/Dubai

AF Asia/Kabul

AG America/Antigua

AI America/Anguilla

AL Europe/Tirane

AM Asia/Yerevan

AN America/Curacao

AO Africa/Luanda

AQ Antarctica/McMurdo

AQ Antarctica/South_Pole

AQ Antarctica/Palmer

AQ Antarctica/Mawson

AQ Antarctica/Davis

AQ Antarctica/Casey

AQ Antarctica/DumontDUrville

AR America/Buenos_Aires

AR America/Rosario

AR America/Cordoba

AR America/Jujuy

AR America/Catamarca

AR America/Mendoza

AS Pacific/Pago_Pago

AT Europe/Vienna

AU Australia/Lord_Howe

AU Australia/Hobart

AU Australia/Melbourne

AU Australia/Sydney

AU Australia/Broken_Hill

AU Australia/Brisbane

AU Australia/Lindeman

AU Australia/Adelaide

AU Australia/Darwin

AU Australia/Perth

AW America/Aruba

AZ Asia/Baku

BA Europe/Sarajevo

BB America/Barbados

BD Asia/Dacca

BE Europe/Brussels

BF Africa/Ouagadougou

BG Europe/Sofia

BH Asia/Bahrain

BI Africa/Bujumbura

BJ Africa/Porto-Novo

BM Atlantic/Bermuda

BN Asia/Brunei

BO America/La_Paz

BR America/Noronha

BR America/Belem

BR America/Fortaleza

BR America/Araguaina

BR America/Maceio

BR America/Sao_Paulo

BR America/Cuiaba

BR America/Porto_Velho

BR America/Manaus

BR America/Porto_Acre

BS America/Nassau

BT Asia/Thimbu

BW Africa/Gaborone

BY Europe/Minsk

BZ America/Belize

CA America/St_Johns

CA America/Halifax

CA America/Glace_Bay

CA America/Goose_Bay

CA America/Pangnirtung

CA America/Montreal

CA America/Nipigon

CA America/Thunder_Bay

CA America/Iqaluit

CA America/Winnipeg

CA America/Rainy_River

CA America/Rankin_Inlet

CA America/Regina

CA America/Swift_Current

CA America/Edmonton

CA America/Yellowknife

CA America/Inuvik

CA America/Dawson_Creek

CA America/Vancouver

CA America/Whitehorse

CA America/Dawson

CC Indian/Cocos

CD Africa/Kinshasa

CD Africa/Lubumbashi

CF Africa/Bangui

CG Africa/Brazzaville

CH Europe/Zurich

CI Africa/Abidjan

CK Pacific/Rarotonga

CL America/Santiago

CL Pacific/Easter

CM Africa/Douala

CN Asia/Harbin

CN Asia/Shanghai

CN Asia/Hong_Kong

CN Asia/Chungking

CN Asia/Urumqi

CN Asia/Kashgar

CO America/Bogota

CR America/Costa_Rica

CU America/Havana

CV Atlantic/Cape_Verde

CX Indian/Christmas

CY Asia/Nicosia

CZ Europe/Prague

DE Europe/Berlin

DJ Africa/Djibouti

DK Europe/Copenhagen

DM America/Dominica

DO America/Santo_Domingo

DZ Africa/Algiers

EC America/Guayaquil

EC Pacific/Galapagos

EE Europe/Tallinn

EG Africa/Cairo

EH Africa/El_Aaiun

ER Africa/Asmera

ES Europe/Madrid

ES Africa/Ceuta

ES Atlantic/Canary

ET Africa/Addis_Ababa

FI Europe/Helsinki

FJ Pacific/Fiji

FK Atlantic/Stanley

FM Pacific/Yap

FM Pacific/Truk

FM Pacific/Ponape

FM Pacific/Kosrae

FO Atlantic/Faeroe

FR Europe/Paris

GA Africa/Libreville

GB Europe/London

GB Europe/Belfast

GD America/Grenada

GE Asia/Tbilisi

GF America/Cayenne

GH Africa/Accra

GI Europe/Gibraltar

GL America/Scoresbysund

GL America/Godthab

GL America/Thule

GM Africa/Banjul

GN Africa/Conakry

GP America/Guadeloupe

GQ Africa/Malabo

GR Europe/Athens

GS Atlantic/South_Georgia

GT America/Guatemala

GU Pacific/Guam

GW Africa/Bissau

GY America/Guyana

HN America/Tegucigalpa

HR Europe/Zagreb

HT America/Port-au-Prince

HU Europe/Budapest

ID Asia/Jakarta

ID Asia/Ujung_Pandang

ID Asia/Jayapura

IE Europe/Dublin

IL Asia/Jerusalem

IN Asia/Calcutta

IO Indian/Chagos

IQ Asia/Baghdad

IR Asia/Tehran

IS Atlantic/Reykjavik

IT Europe/Rome

JM America/Jamaica

JO Asia/Amman

JP Asia/Tokyo

KE Africa/Nairobi

KG Asia/Bishkek

KH Asia/Phnom_Penh

KI Pacific/Tarawa

KI Pacific/Enderbury

KI Pacific/Kiritimati

KM Indian/Comoro

KN America/St_Kitts

KP Asia/Pyongyang

KR Asia/Seoul

KW Asia/Kuwait

KY America/Cayman

KZ Asia/Almaty

KZ Asia/Aqtobe

KZ Asia/Aqtau

LA Asia/Vientiane

LB Asia/Beirut

LC America/St_Lucia

LI Europe/Vaduz

LK Asia/Colombo

LR Africa/Monrovia

LS Africa/Maseru

LT Europe/Vilnius

LU Europe/Luxembourg

LV Europe/Riga

LY Africa/Tripoli

MA Africa/Casablanca

MC Europe/Monaco

MD Europe/Chisinau

MG Indian/Antananarivo

MH Pacific/Majuro

MH Pacific/Kwajalein

MK Europe/Skopje

ML Africa/Bamako

ML Africa/Timbuktu

MM Asia/Rangoon

MN Asia/Ulan_Bator

MO Asia/Macao

MP Pacific/Saipan

MQ America/Martinique

MR Africa/Nouakchott

MS America/Montserrat

MT Europe/Malta

MU Indian/Mauritius

MV Indian/Maldives

MW Africa/Blantyre

MX America/Cancun

MX America/Mexico_City

MX America/Mazatlan

MX America/Chihuahua

MX America/Ensenada

MX America/Tijuana

MY Asia/Kuala_Lumpur

MY Asia/Kuching

MZ Africa/Maputo

NA Africa/Windhoek

NC Pacific/Noumea

NE Africa/Niamey

NF Pacific/Norfolk

NG Africa/Lagos

NI America/Managua

NL Europe/Amsterdam

NO Europe/Oslo

NP Asia/Katmandu

NR Pacific/Nauru

NU Pacific/Niue

NZ Pacific/Auckland

NZ Pacific/Chatham

OM Asia/Muscat

PA America/Panama

PE America/Lima

PF Pacific/Tahiti

PF Pacific/Marquesas

PF Pacific/Gambier

PG Pacific/Port_Moresby

PH Asia/Manila

PK Asia/Karachi

PL Europe/Warsaw

PM America/Miquelon

PN Pacific/Pitcairn

PR America/Puerto_Rico

PS Asia/Gaza

PT Europe/Lisbon

PT Atlantic/Madeira

PT Atlantic/Azores

PW Pacific/Palau

PY America/Asuncion

QA Asia/Qatar

RE Indian/Reunion

RO Europe/Bucharest

RU Europe/Kaliningrad

RU Europe/Moscow

RU Europe/Samara

RU Asia/Yekaterinburg

RU Asia/Omsk

RU Asia/Novosibirsk

RU Asia/Krasnoyarsk

RU Asia/Irkutsk

RU Asia/Yakutsk

RU Asia/Vladivostok

RU Asia/Magadan

RU Asia/Kamchatka

RU Asia/Anadyr

RW Africa/Kigali

SA Asia/Riyadh

SB Pacific/Guadalcanal

SC Indian/Mahe

SD Africa/Khartoum

SE Europe/Stockholm

SG Asia/Singapore

SH Atlantic/St_Helena

SI Europe/Ljubljana

SJ Arctic/Longyearbyen

SJ Atlantic/Jan_Mayen

SK Europe/Bratislava

SL Africa/Freetown

SM Europe/San_Marino

SN Africa/Dakar

SO Africa/Mogadishu

SR America/Paramaribo

ST Africa/Sao_Tome

SV America/El_Salvador

SY Asia/Damascus

SZ Africa/Mbabane

TC America/Grand_Turk

TD Africa/Ndjamena

TF Indian/Kerguelen

TG Africa/Lome

TH Asia/Bangkok

TJ Asia/Dushanbe

TK Pacific/Fakaofo

TM Asia/Ashkhabad

TN Africa/Tunis

TO Pacific/Tongatapu

TR Europe/Istanbul

TT America/Port_of_Spain

TV Pacific/Funafuti

TW Asia/Taipei

TZ Africa/Dar_es_Salaam

UA Europe/Kiev

UA Europe/Simferopol

UG Africa/Kampala

UM Pacific/Johnston

UM Pacific/Midway

UM Pacific/Wake

US America/New_York

US America/Detroit

US America/Louisville

US America/Indianapolis

US America/Indiana/Marengo

US America/Indiana/Knox

US America/Indiana/Vevay

US America/Chicago

US America/Menominee

US America/Denver

US America/Boise

US America/Shiprock

US America/Phoenix

US America/Los_Angeles

US America/Anchorage

US America/Juneau

US America/Yakutat

US America/Nome

US America/Adak

US Pacific/Honolulu

UY America/Montevideo

UZ Asia/Samarkand

UZ Asia/Tashkent

VA Europe/Vatican

VC America/St_Vincent

VE America/Caracas

VG America/Tortola

VI America/St_Thomas

VN Asia/Saigon

VU Pacific/Efate

WF Pacific/Wallis

WS Pacific/Apia

YE Asia/Aden

YT Indian/Mayotte

YU Europe/Belgrade

ZA Africa/Johannesburg

ZM Africa/Lusaka

ZW Africa/Harare

---