Please take a look at this picture of mail-tester.com saying that Your DKIM signature is not valid.
As you can see, the DKIM signature and public key are identical in term of text (characters) but the only problem is the spaces between them. I do not know how to fix this, or what is the proper way to edit a DKIM from zone record. Currently, I try to copy the DKIM signature shown in the page and manually paste it over to the DNS TXT record (public key). After refreshing the page, it passes the test, but after making another request, the spaces disappear and the test failed again.
What is the correct way to correct the DKIM public key so it matches the DKIM of the signature?