I tried to paste the code generated through Google Tag Manager to my blog and I verified that the code was copied exactly, but always I get the same message error:
"The reference to entity "l" must end with the ';' delimiter"
I found this from Claudia
This is a problem with blogger and GTM - blogger parses everything as XML which causes problems with the GTM tag. Try the following: In the code of your container tag you should see this line
replace that line with this line - the change is highlighted in bold
Then copy the adjusted code in your blogger template and save the template - it should work now. When you then check the source code of the website you can see that the '&' has been changed back by blogger to the correct '&', so the code that is actually included on the website is exactly the code that GTM requires.