Looking for logging into the Merchant Center site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Merchant Center site. After that you can login as usual with your login credentials.
https://www.google.com/retail/solutions/merchant-center/
https://www.google.pl/retail/solutions/merchant-center/
https://support.google.com/merchants/answer/188493?hl=pl
https://accounts.google.com/Login?service=merchants
https://www.google.be/intl/de/retail/solutions/merchant-center/
https://www.groupon.pl/merchant/center/login
https://www.en.advertisercommunity.com/t5/Shopping-and-Merchant-Center/Cannot-log-into-Merchant-Center-Adwords-account-active/td-p/462436
https://www.en.advertisercommunity.com/t5/Shopping-and-Merchant-Center/MCA-Multi-Client-Account-Can-t-login/td-p/1107595
https://merchants.worldpay.us/
https://www.groupon.com/merchant/center
https://quickbooks.intuit.com/community/Payments/Log-in-to-the-merchant-service-center-from-inside-QuickBooks/td-p/185749
https://www.secure-fastcharge.com/
https://www.myprismpay.com/