I have a lightning button I created with the API name of "Merge_ADV" It's a detail page button with a URL source content. Here's the button:
/apex/APXTConga4__Conga_Composer 
?serverUrl={!API.Partner_Server_URL_290} 
&id={!Account.Id} 
&templateid=a2J0V000001jNnn,a2J0V000001jNns,a2J0V000001jNo3,a2J0V000001jNo7,a2J0V000001jNoH,a2J0V000001jNnx,a2J0V000001jNnt,{!Account.ADV_Template_ID__c}&OFN+ENG]&AWD=1

I keep getting this error:
The name can only contain underscores and alphanumeric characters. It must begin with a letter and be unique, and must not include spaces, end with an underscore, or contain two consecutive underscores. 
 
Any help is appreciated.