To fix this issue,
Login to your database using phpMyAdmin
Go to Table: user_groups
Update the column permission with the below given value for user_group_id = 1 (i.e administrator).
{"access":["analytics\/google_analytics","captcha\/basic_captcha","captcha\/google_captcha","catalog\/attribute","catalog\/attribute_group","catalog\/category","catalog\/download","catalog\/filter","catalog\/information","catalog\/manufacturer","catalog\/option","catalog\/product","catalog\/recurring","catalog\/review","common\/column_left","common\/filemanager","common\/menu","common\/profile","common\/stats","customer\/custom_field","customer\/customer","customer\/customer_group","design\/banner","design\/layout","extension\/analytics","extension\/captcha","extension\/feed","extension\/fraud","extension\/installer","extension\/modification","extension\/module","extension\/openbay","extension\/payment","extension\/shipping","extension\/total","feed\/google_base","feed\/google_sitemap","feed\/openbaypro","fraud\/fraudlabspro","fraud\/ip","fraud\/maxmind","localisation\/country","localisation\/currency","localisation\/geo_zone","localisation\/language","localisation\/length_class","localisation\/location","localisation\/order_status","localisation\/return_action","localisation\/return_reason","localisation\/return_status","localisation\/stock_status","localisation\/tax_class","localisation\/tax_rate","localisation\/weight_class","localisation\/zone","marketing\/affiliate","marketing\/contact","marketing\/coupon","marketing\/marketing","module\/account","module\/affiliate","module\/amazon_login","module\/amazon_pay","module\/banner","module\/bestseller","module\/carousel","module\/category","module\/ebay_listing","module\/featured","module\/filter","module\/google_hangouts","module\/html","module\/information","module\/latest","module\/pp_button","module\/pp_login","module\/slideshow","module\/special","module\/store","openbay\/amazon","openbay\/amazon_listing","openbay\/amazon_product","openbay\/amazonus","openbay\/amazonus_listing","openbay\/amazonus_product","openbay\/ebay","openbay\/ebay_profile","openbay\/ebay_template","openbay\/etsy","openbay\/etsy_product","openbay\/etsy_shipping","openbay\/etsy_shop","payment\/amazon_login_pay","payment\/authorizenet_aim","payment\/authorizenet_sim","payment\/bank_transfer","payment\/bluepay_hosted","payment\/bluepay_redirect","payment\/cheque","payment\/cod","payment\/firstdata","payment\/firstdata_remote","payment\/free_checkout","payment\/g2apay","payment\/globalpay","payment\/globalpay_remote","payment\/klarna_account","payment\/klarna_invoice","payment\/liqpay","payment\/nochex","payment\/paymate","payment\/paypoint","payment\/payza","payment\/perpetual_payments","payment\/pp_express","payment\/pp_payflow","payment\/pp_payflow_iframe","payment\/pp_pro","payment\/pp_pro_iframe","payment\/pp_standard","payment\/realex","payment\/realex_remote","payment\/sagepay_direct","payment\/sagepay_server","payment\/sagepay_us","payment\/securetrading_pp","payment\/securetrading_ws","payment\/skrill","payment\/twocheckout","payment\/web_payment_software","payment\/worldpay","report\/affiliate","report\/affiliate_activity","report\/affiliate_login","report\/customer_activity","report\/customer_credit","report\/customer_login","report\/customer_online","report\/customer_order","report\/customer_reward","report\/marketing","report\/product_purchased","report\/product_viewed","report\/sale_coupon","report\/sale_order","report\/sale_return","report\/sale_shipping","report\/sale_tax","sale\/order","sale\/recurring","sale\/return","sale\/voucher","sale\/voucher_theme","setting\/setting","setting\/store","shipping\/auspost","shipping\/citylink","shipping\/fedex","shipping\/flat","shipping\/free","shipping\/item","shipping\/parcelforce_48","shipping\/pickup","shipping\/royal_mail","shipping\/ups","shipping\/usps","shipping\/weight","tool\/backup","tool\/error_log","tool\/upload","total\/coupon","total\/credit","total\/handling","total\/klarna_fee","total\/low_order_fee","total\/reward","total\/shipping","total\/sub_total","total\/tax","total\/total","total\/voucher","user\/api","user\/user","user\/user_permission"],"modify":["analytics\/google_analytics","captcha\/basic_captcha","captcha\/google_captcha","catalog\/attribute","catalog\/attribute_group","catalog\/category","catalog\/download","catalog\/filter","catalog\/information","catalog\/manufacturer","catalog\/option","catalog\/product","catalog\/recurring","catalog\/review","common\/column_left","common\/filemanager","common\/menu","common\/profile","common\/stats","customer\/custom_field","customer\/customer","customer\/customer_group","design\/banner","design\/layout","extension\/analytics","extension\/captcha","extension\/feed","extension\/fraud","extension\/installer","extension\/modification","extension\/module","extension\/openbay","extension\/payment","extension\/shipping","extension\/total","feed\/google_base","feed\/google_sitemap","feed\/openbaypro","fraud\/fraudlabspro","fraud\/ip","fraud\/maxmind","localisation\/country","localisation\/currency","localisation\/geo_zone","localisation\/language","localisation\/length_class","localisation\/location","localisation\/order_status","localisation\/return_action","localisation\/return_reason","localisation\/return_status","localisation\/stock_status","localisation\/tax_class","localisation\/tax_rate","localisation\/weight_class","localisation\/zone","marketing\/affiliate","marketing\/contact","marketing\/coupon","marketing\/marketing","module\/account","module\/affiliate","module\/amazon_login","module\/amazon_pay","module\/banner","module\/bestseller","module\/carousel","module\/category","module\/ebay_listing","module\/featured","module\/filter","module\/google_hangouts","module\/html","module\/information","module\/latest","module\/pp_button","module\/pp_login","module\/slideshow","module\/special","module\/store","openbay\/amazon","openbay\/amazon_listing","openbay\/amazon_product","openbay\/amazonus","openbay\/amazonus_listing","openbay\/amazonus_product","openbay\/ebay","openbay\/ebay_profile","openbay\/ebay_template","openbay\/etsy","openbay\/etsy_product","openbay\/etsy_shipping","openbay\/etsy_shop","payment\/amazon_login_pay","payment\/authorizenet_aim","payment\/authorizenet_sim","payment\/bank_transfer","payment\/bluepay_hosted","payment\/bluepay_redirect","payment\/cheque","payment\/cod","payment\/firstdata","payment\/firstdata_remote","payment\/free_checkout","payment\/g2apay","payment\/globalpay","payment\/globalpay_remote","payment\/klarna_account","payment\/klarna_invoice","payment\/liqpay","payment\/nochex","payment\/paymate","payment\/paypoint","payment\/payza","payment\/perpetual_payments","payment\/pp_express","payment\/pp_payflow","payment\/pp_payflow_iframe","payment\/pp_pro","payment\/pp_pro_iframe","payment\/pp_standard","payment\/realex","payment\/realex_remote","payment\/sagepay_direct","payment\/sagepay_server","payment\/sagepay_us","payment\/securetrading_pp","payment\/securetrading_ws","payment\/skrill","payment\/twocheckout","payment\/web_payment_software","payment\/worldpay","report\/affiliate","report\/affiliate_activity","report\/affiliate_login","report\/customer_activity","report\/customer_credit","report\/customer_login","report\/customer_online","report\/customer_order","report\/customer_reward","report\/marketing","report\/product_purchased","report\/product_viewed","report\/sale_coupon","report\/sale_order","report\/sale_return","report\/sale_shipping","report\/sale_tax","sale\/order","sale\/recurring","sale\/return","sale\/voucher","sale\/voucher_theme","setting\/setting","setting\/store","shipping\/auspost","shipping\/citylink","shipping\/fedex","shipping\/flat","shipping\/free","shipping\/item","shipping\/parcelforce_48","shipping\/pickup","shipping\/royal_mail","shipping\/ups","shipping\/usps","shipping\/weight","tool\/backup","tool\/error_log","tool\/upload","total\/coupon","total\/credit","total\/handling","total\/klarna_fee","total\/low_order_fee","total\/reward","total\/shipping","total\/sub_total","total\/tax","total\/total","total\/voucher","user\/api","user\/user","user\/user_permission"]}