table full error 1114 when altering table to add column (no replies)

We are using mysql 5.7.24 ndb-7.6.8

Trying to alter a table to add a column and I get the table full error 1114

There is plenty of disk space and I have checked the following

mysql> show variables like "innodb_data_file_path";
+-----------------------+------------------------+
| Variable_name | Value |
+-----------------------+------------------------+
| innodb_data_file_path | ibdata1:12M:autoextend |
+-----------------------+------------------------+

ndb_mgm> all report mem
Node 3: Data usage is 14%(37444 32K pages of total 254686)
Node 3: Index usage is 0%(1314 32K pages of total 218556)
Node 4: Data usage is 14%(37445 32K pages of total 254686)
Node 4: Index usage is 0%(1314 32K pages of total 218555)

What else is there to check? Urgent need!

John Jones