It has been more than 6 weeks that I filed my tax refund through mail (not e-file). And is not even showing in Where is my Refund Page. What should I do?

Expect it to take at least four weeks for information about a mailed tax return to show up on the IRS site.  It might take longer.   A human has to enter the information into the system.   Did you use certified mail so you would have confirmation that the mailed return was received?  (If not, in the future--always use a service with tracking when you mail anything to the IRS).

Your ONLY source of information about your refund now is the IRS.

You need your filing status, your Social Security number and the exact amount  (line 35a of your 2023 Form 1040) of your federal refund to track your Federal refund:   

https://www.irs.gov/refunds

To track your state refund:    

https://ttlc.intuit.com/questions/1899433-how-do-i-track-my-state-refund

Call the IRS: 1-800-829-1040 hours 7 AM - 7 PM local time Monday-Friday
When calling the IRS do NOT choose the first option re: "Refund", or it will send you to an automated phone line.
So after first choosing your language, then do NOT choose Option 1 (refund info). Choose option 2 for "personal income tax" instead.
Then press 1 for "form, tax history, or payment".
Then press 3 "for all other questions."
Then press 2 "for all other questions."
- When it asks you to enter your SSN or EIN to access your account information, don't enter anything.
- After it asks twice, you will get another menu.

Press 2 for personal or individual tax questions.
Then press 3 for all other inquiries
It should then transfer you to an agent.